“Slumdog Millionaire,” the Cinderella story of a Mumbai orphan who rises from rags to riches, swept the 81st Academy Awards in Hollywood Sunday night, winning all eight categories in which it was nominated, including best picture and director.

It was a stunning triumph for a film that, not unlike its hero, was orphaned by one distributor before it was picked up by another and adopted by audiences around the world.

On her sixth Oscar nomination, Kate Winslet won the lead-actress prize for her role as a German tram conductor with two dark secrets in “The Reader.” As she caressed her statuette she looked at another nominee and said, “I can’t believe we’re in the same category as Meryl Streep!” Spanish beauty Penelope Cruz took supporting actress honors for “Vicky Christina Barcelona.”

“I know how hard I make it to appreciate me,” quipped the smiling Sean Penn, receiving his second Oscar for his charismatic performance as San Francisco political activist Harvey Milk in “Milk.” And Heath Ledger was named best supporting actor for his turn as the diabolical Joker in “The Dark Knight.”

“Slumdog’s” Danny Boyle, honored for his lively direction, praised his collaborators with “You dwarf even the sky.” The movie was also cited for Simon Beaufoy’s screenplay, adapted from the novel “Q & A” by Vikas Swarup. “Slumdog’s” other honors included statuettes for Anthony Dod Mantle’s kinetic cinematography; A.R. Rahman’s world-beat score that blended Bollywood music with hip-hop rhythms; its rollicking best song, “Jai Ho”; its layered sound capturing the cacophony of Mumbai; and its supersonic editing that made the story fly by.

For his role as the mercurial and menacing Joker in “The Dark Knight,” the late Ledger became only the second performer (after Peter Finch) to win a posthumous acting prize. Ledger’s parents and sister accepted the award on his behalf. The award will go to “your beautiful Matilda” (Ledger’s 3-year-old daughter), said his sister, Kate.

Cruz, 34, won the best supporting actress award for her role as the fiery ex-wife in the Woody Allen-directed “Vicky Cristina Barcelona.” “Art is the universal language,” Cruz said, before thanking her countrymen in Spanish.

“The Curious Case of Benjamin Button,” which led the field with 13 nominations, won for its evocative art direction, makeup that made hunk Brad Pitt look like a garden gnome, and visual effects that credibly made Pitt age in reverse from 80 to newborn.

Hollywood hoped that host Hugh Jackman could reinvigorate a ceremony that has been slipping in relevance, and ratings, for the last decade. In the opening sequence, the charismatic Jackman delivered, with a song-and-dance medley that playfully teased the five best-picture nominees.

Alas, during Jackman’s cluttered, Baz Lurhmann-directed tribute to the movie musical - performed with Beyonce and the stars of “High School Musical” and “Mamma Mia!” - one could almost hear remote controls across America changing channels.

The much-hyped new Oscar format, with a redesigned stage and more spontaneous presentations, produced mixed results. Jackman was convivial, but his presence was too sporadic to lighten the 3 ½-hour show.

Fresher was a Judd Apatow-directed segment featuring “Pineapple Express” stars James Franco and Seth Rogen in character as stoners who couldn’t tell the difference between nominated dramas and comedies.

In a welcome break from tradition, Oscar-winning actors of the past offered moving tributes to this year’s nominated actors, which had the effect of celebrating all the contenders, not just the winners.

“WALL-E,” the love story between a trash-collecting unit and a sleek, white probe robot, was named best animated feature, giving director Andrew Stanton (“Finding Nemo”) his second Oscar.

Dustin Lance Black took the original-screenplay honors for “Milk,” giving the film its second Oscar out of eight nominations. (In truth, it is the third Oscar for slain gay activist Harvey Milk, who also was the subject of a 1984 Oscar-winning documentary).

Of all the winners, Penn was the only one to make an overtly political speech, rallying the audience on behalf of equal rights for gays and lesbians.

As in recent years, this year’s best-picture Oscar was an indie film and not a studio blockbuster. While “The Dark Knight,” the most popular film of 2008 (more than $1 billion worldwide at the box office), had eight nominations, and won two for supporting actor Heath Ledger and its complex sound editing, it was not in contention for best picture.

The best-picture contenders were “Slumdog Millionaire,” “The Curious Case of Benjamin Button,” “Frost/Nixon,” “Milk” and “The Reader.”

The foreign-film winner, “Departures” from Japan, upset the front-runners “Waltz With Bashir” from Israel and “The Class” from France.

“Man on Wire,” James Marsh’s chronicle of French aerialist Philippe Petit’s daring high-wire dance between New York’s twin towers in 1974, won best documentary.

In the year of “Doubt,” the only Oscar certainty was that Jerry Lewis, the funnyman crowned “Le Roi du Crazy” by his French fans, would receive the Jean Hersholt Humanitarian Award. Eddie Murphy, who starred in the remake of Lewis’ “The Nutty Professor,” presented the award to a tearful Lewis.

Since 1952, Lewis, who was a box-office powerhouse and inventor of the video assist that enables directors to view playback of the scene just shot, has raised more than $2 billion for the Muscular Dystrophy Association.

Despite his international fame, and dozens of movies over half a century, Lewis had never been recognized by the Academy, except as a three-time Oscar host.