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LOS ANGELES, Feb 26 (Reuters) - Viola Davis won her first Oscar on Sunday for her supporting role as a long-suffering housewife in the African-American family drama "Fences."

Davis, 51, had swept awards season in the role, taking home a Golden Globe, Screen Actors Guild statuette and numerous critics prizes. She had been nominated for an Oscar twice in the past.

"I became an artist, and thank God I did, because we are the only profession that celebrates what it means to live a life," an emotional Davis said while accepting her statuette.

In "Fences," the screen version of the prize-winning August Wilson play, Davis played Rose Maxson, a self-effacing wife whose modest life implodes when her charismatic husband insists on keeping a mistress.

On stage, Davis heralded Wilson, whom she said "exhumed and exalted the ordinary people."

Davis won a Tony Award in the same role on stage in 2010.

A forceful and popular actress, Davis is known for playing strong women and for speaking out for better roles for women and people of color.

On television, she became the first black woman to win a lead actress Emmy award when she took home the statuette in 2015 for playing a conflicted criminal attorney in drama "How To Get Away With Murder."

Raised in an impoverished household in South Carolina and Rhode Island, Davis began acting as a teen at school and later trained at the Juilliard School in New York.

She began work in the theater, winning early acclaim. After years of doing small parts in movies, she made her breakout with just one scene in the 2008 religious film "Doubt," earning her first Oscar nomination. Three years later she was nominated for best actress for "The Help," but lost out to Meryl Streep.

(Reporting by Jill Serjeant; Editing by Sandra Maler)