Ellen Degeneres: The award for best comic...

... goes to the host of tonight's Oscars. After years in career Siberia, she is having the last laugh

Following the phone call from Oscars producer Laura Ziskin inviting her to host this year's Academy Awards ceremony, Ellen DeGeneres remarked: "There's two things I've always wanted to do in my life. One is to host the Oscars. The second is to get a call from Laura Ziskin. You can imagine that day's diary entry."

Never mind the grammar, feel the triumph.

Owing largely to her own efforts, DeGeneres is America's most celebrated lesbian. Being selected for Hollywood's biggest stand-up gig grants her the Gold Seal of Approval in the eyes of a public who have loved her, loathed her and laughed at her in almost equal measure for over two decades. It may well prove to be the high-water mark for the comedian who surfaced in 1981, scuttled herself in 1997 and sank in 1998.

Three years in showbiz Siberia did little to affect her comic resilience. When she accepted the poison chalice of hosting the Emmys in November 2001 just two months after the tragedy of 9/11, she delivered an opening line that served her career and her country in the best possible manner: "We're told to go on living our lives as usual because to do otherwise is to let the terrorists win, and really, what would upset the Taliban more than a gay woman wearing a suit in front of a room full of Jews?"

Having tested the tolerance of middle Americans beyond their natural limit by coming out in public, she subsequently salvaged her career, established the strength of her position as one of the funniest women on the planet and dealt a blow for gay rights simultaneously. In the same year she voiced the character of Dory, the fish with short-term memory loss, in Finding Nemo, making her the most memorable character in the animated film.

Even so, the path to redemption has not always been strewn with roses.

First, there was the fuss over the publication of an autobiography by her former girlfriend, Anne Heche. Incensed by the claims made about her bizarre and damaging home life as a child, Anne's mother attempted to summon DeGeneres as character witness to build a case in court against Anne.

In 2006, DeGeneres was again involved in a public tussle with another former lover, Alexandra Hedison, who was unable to accept that she had been replaced in the comedian's affections by Portia de Rossi, who played Nelle in Ally McBeal, and was asked to leave the Los Angeles home she and DeGeneres had shared for four years. Ellen and Portia are still together, and live in Hollywood.

Neither of these events has affected her resurrected career, however, and her NBC daytime talk show remains as popular as ever. The 49-year-old is not about to go down for a second time.

Ellen DeGeneres was born on 26 January 1958 in Metairie, Louisiana, a suburb of New Orleans, to insurance salesman Elliot De Generes and Elizabeth, an estate agent. Ellen and her brother, Vance, were raised as Christian Scientists. Her parents divorced when Ellen was 16 and her mother then married salesman Roy Gruessendorf, who moved the family to Atlanta, Texas.

After graduating from Atlanta High School in 1976, Ellen moved back to New Orleans to attend university as a communication major, but dropped out after a year to work as a paralegal in a law firm. Her poor facility for academic study meant she had to abandon her original ambition to be a vet. While drifting through a variety of jobs, DeGeneres was much in demand by her friends for parties when she would perform her embryonic stand-up act.

She made her debut on amateur night at a New Orleans coffee shop in 1981. Within a year, she won Showtime's Funniest Person in America competition. Her style was always generally good-natured and non-political, evolving around her persona as a well-meaning tomboyish girl who always manages to say or do the wrong thing.

In 1986, chat show host Johnny Carson bestowed the ultimate accolade when she became the first female comic to share his couch on a debut appearance. In 1988, she had a supporting role in the sitcom Duet, and later she turned down an offer to be one of the friends on Friends. She got her own show, These Friends of Mine, which was eventually renamed Ellen and the die was cast.

While Ellen looked set for a long run, DeGeneres made a few forays into films, though her choices were not always of the best. She turned down the Sandra Bullock role in Speed and instead played opposite Bill Paxton in Mr Wrong.

On 30 April 1997, DeGeneres came out of the closet on Ellen; the episode received huge ratings and media attention, put DeGeneres on the cover of Time magazine, and made Ellen the first network series with an out-gay lead character.

Television evangelist Jerry Falwell called her "Ellen Degenerate". Sadly for him, it was a joke she'd been hearing, she said, "since fourth grade". The day after she came out, the ABC affiliate in Birmingham, Alabama, dropped the show. Owing to pressure from sponsors and advertisers, the ratings dropped and the show was cancelled in 1998.

Coming out may have stalled her career but it had peripheral benefits. "As soon as I made this decision, I lost weight and my skin cleared up," she said at the time. "No one can hurt me now."

Words spoken in haste, it now seems, as DeGeneres made the mistake of flaunting her sexuality in the face of the American public with her new lover, Anne Heche, notably at a black-tie Washington dinner. The first celebrity lesbian couple, they took place of honour at Bill Clinton's table where DeGeneres appeared, as one correspondent put it, with Heche "on her arm and occasionally around her neck". Their excitement at busting the taboo was palpable, but it wasn't to last. Heche's career suffered even more than Degeneres'. They separated shortly afterwards.

DeGeneres' comic style is often compared with that of Bob Newhart, who leapt to her defence in her time of trouble. He said: "DeGeneres is the bravest and most honest female comedian I have ever seen work because she publicly announced she's gay. That revelation could have ended her career, as she had to be aware, but she also knew she had to be honest."

Her greatest supporter is her mother, Betty, who is, by her own admission, "hopelessly heterosexual". Yet she is now a leading campaigner for gay and lesbian rights throughout America and the first non-gay spokesperson for the US national coming-out project.

One of the wittiest lines ever delivered at the Oscars ceremony was the closing remark by host Steve Martin in 2002, following the anti-Bush speech given by Michael Moore after receiving the best documentary Oscar for Bowling for Columbine. Having thanked everyone for the efforts behind the scenes, Martin added: "The Teamsters are helping Michael Moore into the trunk of his car."

DeGeneres may well be the only person equipped with enough comedy cool to equal that on Oscar night.