Birdman, a dark satire of show business and fame directed by Alejandro G. Inarritu won the Academy Award for best picture, the film industry's highest honor.
Julianne Moore won the best actress Oscar on Sunday for her role as a university professor with Alzheimer's disease in Still Alice.
The win marked Moore's first Academy Award after being nominated four times previously. The 54-year-old actress was favored to win this year's prize after picking up Golden Globe, Screen Actors Guild and BAFTA awards earlier this year.
British actor Eddie Redmayne won the best actor Oscar for his performance as Professor Stephen Hawking in The Theory of Everything.
JK Simmons and Patricia Arquette won their first Academy Awards at Oscars 2015 when they were bestowed with the Best Performance by an Actor and Actress in Supporting Role for their work in Whiplash and Boyhood respectively. Polish director Pawel Pawlikowski went from directing a black-and-white movie that inspires silent contemplation to being at the "epicenter of noise," the Oscars, he said visibly amused, as he accepted the prize for best foreign film for "Ida".
The 87th Academy Awards rolled out to a rapturous welcome with host Neil Patrick Harris launching the show, after Hollywood's brightest walked up a rain-soaked Oscars red carpet.
Dark comedy Birdman and coming-of-age drama Boyhood are widely expected to duel it out for the top prize of the night, best picture, to be awarded at the climax of the more than three-hour show.
Harris, hosting his first Oscars, kicked off the proceedings on an edgy note, saying it was a night to celebrate "Hollywood's best and whitest -- sorry, brightest" -- a cutting reference to this year's total lack of non-white acting nominees.
J.K. Simmons took the first Oscar of the evening, winning the best supporting actor prize for his performance in director Damien Chazelle's indie jazz drumming drama Whiplash.
Simmons won the best supporting actor Oscar for playing a bullying jazz teacher in Whiplash, which powerfully explores the limits of sadism and abuse. He bested rivals Robert Duvall (The Judge), Ethan Hawke (Boyhood), Edward Norton (Birdman) and Mark Ruffalo (Foxcatcher).
Simmons, who has been the odds-on favourite in the category after sweeping up trophies throughout Hollywood's awards season, gave a warm speech thanking his wife, children and parents. "If you are lucky enough to have a parent or two alive on this planet, call them. Don't text, don't e-mail. Call them on the phone," he told the Oscars audience at the Dolby Theatre.
In Whiplash, Simmons plays Fletcher, a feared top teacher at an elite music conservatory not unlike the famed Julliard School in New York. He notices Andrew, a promising young drummer who has just enrolled at the school, and selects him for a school jazz band entered in a nationwide competition.
At first, Fletcher treats his new recruits with kid gloves, gaining their confidence and earning their admiration. But then, playing on rivalry between students, he turns on them, abusing them mentally and physically -- he justifies throwing a cymbal at Andrew (played by Miles Teller) by noting that that's how Charlie Parker became a legend.
Simmons -- who himself studied music before turning to acting -- won both the Golden Globe and the Screen Actors Guild award for his role in the film, only the second feature from director Damien Chazelle.
The Oscar crowns a more than 30-year career on television and the big screen. While a familiar face at the cinema, he has rarely headlined a film.
Hung around long enough
The 60-year-old actor says the Academy Award success is the result of decades of learning his craft. It "would not have come when I was in my 20s, because I was figuring out how to do this, and it was painful and a struggle -- more for the audience than for myself," he told reporters, self-deprecatingly, at a lunch for Oscar nominees earlier this month.
"I've just hung around long enough and gotten an opportunity to work with enough great people that I've sort of gradually learned over the years how to do this," added Simmons, who grew up in Montana.
The actor -- who is well known in the US for television ads for Farmers Insurance, a fact highlighted in a joke by host Neil Patrick Harris -- regularly lends his voice for dubbing or animated films. Over the years on television, he has played everything from a psychiatrist on the long-running Law and Order, a neo-Nazi in HBO prison drama Oz, and a police officer on The Closer.
On the big screen, he is well known for his turn as J. Jonah Jameson, the tough-as-nails editor of the Daily Bugle in the Spider-Man movies. He has worked several times with the director Jason Reitman who used him in Thank you for Smoking (2005), Juno (2007), 2009's Up in the Air with George Clooney and Men, Women and Children (2014).
Married to the actress and producer Michelle Schumacher, Simmons says that over the years, he has learned "how to listen, how to be there, how to relax. "I continue to be fairly ignorant about many technical aspects of camera acting specifically, and have decided to keep it that way because it just clouds my brain," he added.
Walt Disney's superhero action comedy film Big Hero 6 won the best animated feature film Oscar at the 87th Academy awards for its inspiring story of a teenager robotics prodigy, who forms a superhero team to combat a masked villain.
The Edward Snowden documentary Citizenfour has won the Oscar for best documentary. Laura Poitras' film documents her initial meeting in Hong Kong with Snowden, as well as journalist Glenn Greenwald.
It's an uncommonly intimate view of what became a historic and much debated act: Snowden leaking National Security Agency documents that revealed the previously undisclosed collection of Americans' phone and email records. Snowden was charged under the federal Espionage Act and is currently living in asylum in Russia. Because of the sensitive nature of the footage, Poitras made Citizenfour under intense secrecy and edited it in Germany.
The other nominees Sunday were: Virunga, Last Days of Vietnam, The Salt of the Earth and Finding Vivian Maier.
The 3D computer-animated film, inspired by the Marvel Comics superhero team of the same name, won the first Oscar for its directors Don Hall, Chris Williams and producer Roy Conli.