The movie, which starred Cooper as crackshot gunman Chris Kyle, was nominated for six Academy Awards, including Best Picture, but only landed one prize for Best Sound Editing.
Cooper missed out on the Best Actor award to Brit Eddie Redmayne, but Kyle's widow Taya insists her husband would have been very proud of everything the cast and crew achieved.
Speaking at the awards show, Taya Kyle told America's ABC news, "I'm so grateful for everything that went into this movie. I wanted to be here to represent Chris, obviously, and it's not the ideal time to do that, but I still wanted to embrace everything that he should be here to do with me... He (Cooper) absolutely got it right... He (Kyle) would be absolutely blown away, and he would be his usual humble self, laugh at himself, probably make fun of it in some ways, but deep down, he would be really, really happy... It's (the movie is) something he would be proud of."
Taya Kyle took time out from attending the trial of her husband's accused killer to attend the glitzy awards show. Former marine Eddie Ray Routh, 27, is currently on trial in Texas accused of killing Kyle and his friend Chad Littlefield in February, 2013. He has pleaded not guilty to murder.