Oprah Winfrey (originally Orpah after the Biblical character), was born in Kosciusko, Mississippi, to a Baptist family. There are conflicting reports as to how her name became “Oprah.” According to a 1991 interview with the Academy of Achievement, Winfrey claimed that her family and friends' inability to pronounce “Orpah” caused them to put the “P” before the “R” in every place else other than the birth certificate. However, there is the account that the midwife transposed letters while filling out the newborn's birth certificate. Her parents were unmarried teenagers. Her mother, Vernita Lee, was a housemaid, and her father, Vernon Winfrey, was a coal miner and later worked as a barber before becoming a city councilman. Winfrey's father was in the Armed Forces when she was born. After her birth, Winfrey's mother travelled north and Winfrey spent her first six years living in rural poverty with her grandmother, Hattie Mae. Winfrey's grandmother taught her to read before the age of three and took her to the local church, where she was nicknamed "The Preacher" for her ability to recite Bible verses. When Winfrey was a child, her grandmother would take a switch and would hit her with it when she didn't do chores or if she misbehaved in any way.

At age six, Winfrey moved to an inner city ghetto in Milwaukee, Wisconsin with her mother, who was less supportive and encouraging than her grandmother. Winfrey has stated that she was molested by her cousin, uncle, and a family friend, starting when she was nine years old.

Despite her dysfunctional home life, Winfrey skipped two of her earliest grades, became the teacher's pet, and by the time she was 13 received a scholarship to attend Nicolet High School in the Milwaukee suburb of Glendale, Wisconsin. Although Winfrey was very popular, she couldn't afford to go out on the town as frequently as her better-off classmates. Like many teenagers at the end of the 1960s, Winfrey rebelled, ran away from home and ran to the streets. When she was 14, she became pregnant, but the baby died shortly after birth. Also at that age, her frustrated mother sent her to live with her father in Nashville, Tennessee. Vernon was strict, but encouraging and made her education a priority. Winfrey became an honors student, was voted Most Popular Girl, joined her high school speech team, and placed second in the nation in dramatic interpretation. She won an oratory contest, which secured her a full scholarship to Tennessee State University, a historically black institution, where she studied communication. At age 18, Winfrey won the Miss Black Tennessee beauty pageant.

Winfrey's grandmother had said that ever since Winfrey could talk, she was on stage. As a child she played games interviewing her corncob doll and the crows on the fence of her family's property. At 17 Winfrey worked at a local radio station while attending Tennessee State University.

Working in local media, she was both the youngest news anchor and the first black female news anchor at Nashville's WLAC-TV. She moved to Baltimore's WJZ-TV in 1976 to co-anchor the six o'clock news. She was then recruited to join Richard Sher as co-host of WJZ's local talk show People Are Talking, which premiered on August 14, 1978. She also hosted the local version of Dialing for Dollars there as well.

In 1983, Winfrey relocated to Chicago to host WLS-TV's low-rated half-hour morning talk-show, AM Chicago. The first episode aired on January 2, 1984. Within months after Winfrey took over, the show went from last place in the ratings to overtaking Donahue as the highest rated talk show in Chicago. It was renamed The Oprah Winfrey Show, expanded to a full hour, and broadcast nationally beginning September 8, 1986. On her 20th anniversary show, Oprah revealed that movie critic Roger Ebert was the one who persuaded her to sign a syndication deal with King World. Ebert predicted that she would generate 40 times as much revenue as his television show, At the Movies. Already having surpassed Donahue in the local market, Winfrey's syndicated show quickly doubled his national audience, displacing Donahue as the number one day-time talk show in America. Their much publicized contest was the subject of enormous scrutiny.

Time magazine wrote, "Few people would have bet on Oprah Winfrey's swift rise to host of the most popular talk show on TV. In a field dominated by white males, she is a black female of ample bulk. As interviewers go, she is no match for, say, Phil Donahue...What she lacks in journalistic toughness, she makes up for in plainspoken curiosity, robust humor and, above all empathy. Guests with sad stories to tell are apt to rouse a tear in Oprah's eye...They, in turn, often find themselves revealing things they would not imagine telling anyone, much less a national TV audience. It is the talk show as a group therapy session."

TV columnist Howard Rosenberg said, "She's a roundhouse, a full course meal, big, brassy, loud, aggressive, hyper, laughable, lovable, soulful, tender, low-down, earthy and hungry. And she may know the way to Phil Donahue's jugular."

Newsday's Les Payne observed, "Oprah Winfrey is sharper than Donahue, wittier, more genuine, and far better attuned to her audience, if not the world."

Martha Bayles of The Wall Street Journal wrote, "It's a relief to see a gab-monger with a fond but realistic assessment of her own cultural and religious roots."

In the mid-1990s, Winfrey adopted a less tabloid-oriented format, doing shows about heart disease in women, geopolitics with Lisa Ling, spirituality and meditation, and gift-giving and home decorating shows. She often interviews celebrities on issues that directly involve them in some way, such as cancer, charity work, or substance abuse. In addition, she interviews ordinary people who have done extraordinary things or been involved in important current issues.

In 1993, Winfrey hosted a rare prime-time interview with Michael Jackson which became the fourth most watched event in American television history as well as the most watched interview ever, with an audience of one hundred million. Perhaps Winfrey's most famous recent show was the first episode of the nineteenth season of The Oprah Winfrey Show in the fall of 2004. During the show each member of the audience received a new G6 sedan; the 276 cars were donated by Pontiac as part of a publicity stunt. The show received so much media attention that even the taxes on the cars became controversial.

During a lawsuit against Winfrey (see Influence), she hired Dr. Phil McGraw's company Courtroom Sciences, Inc. to help her analyze and read the jury. Dr. Phil made such an impression on Winfrey that she invited him to appear on her show. He accepted the invitation and was a resounding success. McGraw appeared on The Oprah Winfrey Show for several years before launching his own show, Dr. Phil, in 2002, which was created by Winfrey's production company, Harpo Productions in partnership with Paramount which produced the show.

Winfrey recently made a deal to extend her show until the 2010–2011 season, by which time it will have been on the air for twenty-five years. She plans to host 140 episodes per season, until her final season, when it will return to its current number, 130.

The 2004 Nobel Peace Prize Concert was hosted by Oprah and Tom Cruise. There were musical performances by Cyndi Lauper, Andrea Bocelli, Joss Stone, Chris Botti, Diana Krall, Tony Bennett and others. The concert was broadcasted in the United States on December 23, 2004, by E!.

As well as hosting and appearing on television shows, Winfrey co-founded the women's cable television network Oxygen. She is also the president of Harpo Productions (Oprah spelled backwards).

In 1985, Winfrey co-starred in Steven Spielberg's epic film adaptation of Alice Walker's Pulitzer Prize-winning novel The Color Purple. She earned immediate acclaim as Sofia, the distraught housewife. The following year Winfrey was nominated for an Academy Award for Best Supporting Actress, but she lost to Anjelica Huston. The Color Purple has now been made into a Broadway musical and opened late 2005, with Winfrey credited as a producer.

In October 1998, Winfrey produced and starred in the film Beloved, based upon Toni Morrison's Pulitzer Prize winning novel of the same name. To prepare for her role as Sethe, the protagonist and former slave, Winfrey experienced a 24-hour simulation of the experience of slavery, which included being tied up and blindfolded and left alone in the woods. Despite major advertising, including two episodes of her talk show dedicated solely to the film, and moderate to good critical reviews, Beloved opened to poor box-office results, losing approximately $30 million. Working with delicate subjects, Winfrey managed to keep the cast motivated and inspired. "Here we were working on this project with the heavy underbelly of political and social realism, and she managed to lighten things up", said costar Thandie Newton. "I've worked with a lot of good actors, and I know Oprah hasn't made many films. I was stunned. She's a very strong technical actress and it's because she's so smart. She's acute. She's got a mind like a razor blade."

In 2005, Harpo Productions released another film adaptation of a famous American novel, Zora Neale Hurston's Their Eyes Were Watching God (1937). The made-for-television film Their Eyes Were Watching God was based upon a teleplay by Suzan-Lori Parks, and starred Halle Berry in the lead female role.

She has voiced for Charlotte's Web, the 2006 film as Gussie the goose.

Winfrey publishes two magazines: O, The Oprah Magazine and O at Home. She has co-authored five books; at the announcement of her future weight loss book (to be co-authored with her personal trainer Bob Greene), it was said that her undisclosed advance fee had broken the record for the world's highest book advance fee, previously held by former U.S. President Bill Clinton for his autobiography My Life. In 2002 Fortune called O, the Oprah Magazine the most successful start-up ever in the industry.

On February 9, 2006 it was announced that Winfrey signed a $55 million, three-year contract with XM Satellite Radio to establish a new radio channel. The channel, Oprah & Friends, features popular contributors to The Oprah Winfrey Show and O, The Oprah Magazine including Nate Berkus, Dr. Mehmet Oz, Bob Greene, Dr. Robin Smith and Marianne Williamson. Oprah & Friends began broadcasting at 11:00 AM ET, September 25, 2006, from a new studio at Winfrey's Chicago headquarters. The channel broadcasts 24 hours a day, 7 days a week on XM Radio Channel 156. Winfrey's contract requires her to be on the air 30 minutes a week, 39 weeks a year. The 30-minute weekly show will feature Winfrey with friend Gayle King. Winfrey's audience is extremely loyal and XM hopes that the "Oprah Effect" can have the same effect on XM subscription sales that she does on the New York Times Best Seller list, thanks to her book club.

Winfrey was called "arguably the World's most powerful woman" by CNN and Time.com, "arguably the most influential woman in the World" by the American Spectator, "one of the 100 people who most influenced the 20th Century" and "one of the most influential people" of 2004, 2005, 2006 and 2007 by Time. Winfrey is the only person in the World to have made all five lists. It should be noted that when these publications use the phrase "the World's most influential person" they mean "no single other person on the planet has more clout", not "this person affects the whole World". It should also be noted that Time's list has been criticized for reflecting "a heavily U.S.-centric perspective".

At the end of the 20th century Life listed Winfrey as both the most influential woman and the most influential black person of her generation, and in a cover story profile the magazine called her "America's most powerful woman". Ladies Home Journal also ranked Winfrey number one in their list of the most powerful women in America and senator Barack Obama has said she "may be the most influential woman in the country". In 1998 Winfrey became the first woman and first Black to top Entertainment Weekly's list of the 101 most powerful people in the entertainment industry. In 2003 Winfrey edged out both Superman and Elvis Presley to be named the greatest pop culture icon of all time by VH1. Forbes named her the world's most powerful celebrity in both 2005 and 2007 Columnist Maureen Dowd seems to agree with such assessments:

“ She is the top alpha female in this country. She has more credibility than the president. Other successful women, such as Hillary Clinton and Martha Stewart, had to be publicly slapped down before they could move forward. Even Condi has had to play the protegé with Bush. None of this happened to Oprah — she is a straight ahead success story.”

Vanity Fair wrote:
“ Oprah Winfrey arguably has more influence on the culture than any university president, politician, or religious leader, except perhaps the Pope. ”

Bill O'Reilly said:
“ I mean this is a woman that came from nothing to rise up to be the most powerful woman, I think, in the world. I think Oprah Winfrey is the most powerful woman in the world, not just in America. That's — anybody who goes on her program immediately benefits through the roof. I mean, she has a loyal following; she has credibility; she has talent; and she's done it on her own to become fabulously wealthy and fabulously powerful. ”

Biographer Kitty Kelley states that she has always been “fascinated” by Winfrey:

“ As a woman, she has wielded an unprecedented amount of influence over the American culture and psyche,…There has been no other person in the 20th century whose convictions and values have impacted the American public in such a significant way.… I see her as probably the most powerful woman in our society. I think Oprah has influenced every medium that she's touched.”

Winfrey's influence reaches far beyond pop-culture and into unrelated industries where many believe she has the power to cause enormous market swings and radical price changes with a single comment. During a show about mad cow disease with Howard Lyman (aired on April 16, 1996), Winfrey exclaimed, "It has just stopped me cold from eating another burger!" Texas cattlemen sued her and Lyman in early 1998 for "false defamation of perishable food" and "business disparagement", claiming that Winfrey's remarks subsequently sent cattle prices tumbling, costing beef producers some USD$12 million. On February 26, after a trial spanning over two months in an Amarillo, Texas court in the thick of cattle country, a jury found Winfrey and Lyman were not liable for damages. (After the trial, she received a postcard from Roseanne Barr reading, “Congratulations, you beat the meat!”) In June 2005 the first case of mad cow disease in a cow native to the United States was detected in Texas. The USDA concluded that it was most likely infected in Texas prior to 1997.

In 2005 Winfrey was named the greatest woman in American history as part of a public poll as part of The Greatest American. She was ranked #9 overall on the list of greatest Americans.

Winfrey's reach extends far beyond the shores of the U.S., where 49 million U.S. viewers see her talk show weekly. The show airs in 117 countries around the world “from Australia to Zimbabwe.”

Winfrey has recently exerted political influence, endorsing presidential candidate Barack Obama in the 2008 presidential election. This is the first time she has publically made such an endorsement. Winfrey held a fundraiser for Obama on September 8, 2007 at her Santa Barbara, CA estate. In December 2007, Winfrey joined Obama for a series of rallies in the early primary states of Iowa, New Hampshire, and South Carolina. The Columbia, South Carolina event on December 9, 2007 drew a crowd of nearly 30,000, the largest for any political event of the 2008 presidential election season thus far. In January of 2008, Oprah has signed a deal with Discovery Health to start her own network OWN (Oprah Winfrey Network).