O'Toole, who died Saturday at age 81 at the private Wellington Hospital in London after a long bout of illness, was nominated a record eight times for an Academy Award without taking home a single statue.
He was fearsomely handsome, with burning blue eyes and a penchant for hard living which long outlived his decision to give up alcohol. Broadcaster Michael Parkinson told Sky News television it was hard to be too sad about his passing.
"Peter didn't leave much of life unlived, did he?" he said.
A reformed - but unrepentant - hell-raiser, O'Toole long suffered from ill health. Always thin, he had grown wraithlike in later years, his famously handsome face eroded by years of outrageous drinking.
But nothing diminished his flamboyant manner and candor.
"If you can't do something willingly and joyfully, then don't do it," he once said. "If you give up drinking, don't go moaning about it; go back on the bottle. Do. As. Thou. Wilt."
O'Toole began his acting career as one of the most exciting young talents on the British stage. His 1955 "Hamlet," at the Bristol Old Vic, was critically acclaimed.
International stardom came in David Lean's "Lawrence of Arabia." With only a few minor movie roles behind him, O'Toole was unknown to most moviegoers when they first saw him as T.E. Lawrence, the mythic British World War I soldier and scholar who led an Arab rebellion against the Turks.
His sensitive portrayal of Lawrence's complex character garnered O'Toole his first Oscar nomination, and the spectacularly photographed desert epic remains his best known role. O'Toole was tall, fair and strikingly handsome, and the image of his bright blue eyes peering out of an Arab headdress in Lean's film was unforgettable.
Playwright Noel Coward once said that if O'Toole had been any prettier, they would have had to call the movie "Florence of Arabia."
Prime Minister David Cameron said Sunday the movie was his favorite film, calling O'Toole's performance "stunning."
In 1964's "Becket," O'Toole played King Henry II to Richard Burton's Thomas Becket, and won another Oscar nomination. Burton shared O'Toole's fondness for drinking, and their off-set carousing made headlines.
O'Toole played Henry again in 1968 in "The Lion in Winter," opposite Katharine Hepburn, for his third Oscar nomination.
Four more nominations followed: in 1968 for "Goodbye, Mr. Chips," in 1971 for "The Ruling Class," in 1980 for "The Stunt Man," and in 1982 for "My Favorite Year." It was almost a quarter-century before he received his eighth and last, for "Venus."
Seamus Peter O'Toole was born Aug. 2, 1932, the son of Irish bookie Patrick "Spats" O'Toole and his wife Constance. There is some question about whether Peter was born in Connemara, Ireland, or in Leeds, northern England, where he grew up, but he maintained close links to Ireland, even befriending the country's now-president, Michael D. Higgins.
Ireland and the world have "lost one of the giants of film and theater," Higgins said in a statement.
After a teenage foray into journalism at the Yorkshire Evening Post and national military service with the navy, a young O'Toole auditioned for the Royal Academy of Dramatic Art and won a scholarship.
He went from there to the Bristol Old Vic and soon was on his way to stardom, helped along by an early success in 1959 at London's Royal Court Theatre in "The Long and The Short and The Tall."
The image of the renegade hell-raiser stayed with O'Toole for decades, although he gave up drinking in 1975 following serious health problems and major surgery.
He did not, however, give up smoking unfiltered Gauloises cigarettes in an ebony holder. That and his penchant for green socks, voluminous overcoats and trailing scarves lent him a rakish air and suited his fondness for drama in the old-fashioned "bravura" manner.
A month before his 80th birthday in 2012, O'Toole announced his retirement from a career that he said had fulfilled him emotionally and financially, bringing "me together with fine people, good companions with whom I've shared the inevitable lot of all actors: flops and hits."
"However, it's my belief that one should decide for oneself when it is time to end one's stay," he said. "So I bid the profession a dry-eyed and profoundly grateful farewell."
In retirement, O'Toole said he would focus on the third volume of his memoirs.
Good parts were sometimes few and far between, but "I take whatever good part comes along," O'Toole told The Independent on Sunday newspaper in 1990.
"And if there isn't a good part, then I do anything, just to pay the rent. Money is always a pressure. And waiting for the right part - you could wait forever. So I turn up and do the best I can."
The 1980 "Macbeth" in which he starred was a critical disaster of heroic proportions. But it played to sellout audiences, largely because the savaging by the critics brought out the curiosity seekers.
"The thought of it makes my nose bleed," he said years later.
In 1989, however, O'Toole had a big stage success with "Jeffrey Bernard is Unwell," a comedy about his old drinking buddy, the legendary layabout and ladies' man who wrote The Spectator magazine's weekly "Low Life" column when he was sober enough to do so.
The honorary Oscar came 20 years after his seventh nomination for "My Favorite Year." By then it seemed a safe bet that O'Toole's prospects for another nomination were slim. He was still working regularly, but in smaller roles unlikely to earn awards attention.
O'Toole graciously accepted the honorary award, quipping, "Always a bridesmaid, never a bride, my foot," as he clutched his Oscar statuette.
He had nearly turned down the award, sending a letter asking that the Academy of Motion Picture Arts and Sciences hold off on the honorary Oscar until he turned 80.
Hoping another Oscar-worthy role would come his way, O'Toole wrote: "I am still in the game and might win the bugger outright."
The last chance came in, for "Venus," in which he played a lecherous old actor consigned to roles as feeble-minded royals or aged men on their death beds. By failing again to win, he broke the tie for futility which had been shared with his old drinking buddy, Richard Burton.
O'Toole divorced Welsh actress Sian Phillips in 1979 after 19 years of marriage. The couple had two daughters, Kate and Pat.
A brief relationship with American model Karen Somerville led to the birth of his son Lorcan in 1983, and a change of lifestyle for O'Toole.
After a long custody battle, a U.S. judge ruled Somerville should have her son during school vacations, and O'Toole would have custody during the school year.
"The pirate ship has berthed," he declared, happily taking on the responsibilities of fatherhood. He learned to coach schoolboy cricket and, when he was in a play, the curtain time was moved back to allow him part of the evenings at home with his son.
O'Toole's death was announced by agent Steve Kenis, who said the actor had been ill for some time.
His daughter Kate said the family had already been overwhelmed by the expressions of sympathy.
"In due course there will be a memorial filled with song and good cheer, as he would have wished," she said in the statement.
AP writer Raphael Satter contributed to this report.