During his speech - a rushed one, as Rockwell joked he was trying to win the jet ski that host Jimmy Kimmel teased in his monologue - Rockwell thanked his fellow nominees and "Three Billboards" co-stars Woody Harrelson and Frances McDormand.
Rockwell also shared a cute story about how his parents fostered his love for film.
The actor also injected some humour into his speech, thanking "anyone who has ever looked at a billboard". Whoever was in my age range, Phil Hoffman was the guy. he inspired me.
Rockwell had previously said Hoffman was a friend of his, and both actors were members of the Labyrinth Theater Company.
'If I had a choice I'd let the film speak for itself movies always take five or ten years to be seen as a piece of work that it is, but it's nearly more of an awards season thing that I had to say that, ' he said. Rockwell has swept award seasons thus far, winning the BAFTA Award, the Golden Globe Award and two Screen Actors Guild Awards. She thanked "I, Tonya" writer Steve Rogers for "the gift of LaVona", as well as, "the cast, crew, and bird that elevated my performance".
"When I was 8-years-old I was called into the principal's office and my father was looking very solemn and he said, 'We gotta go, it's grandma, '" recalled Rockwell.
Rockwell and Harrelson's nominations were among seven earned by "Three Billboards".
Rockwell explained that Hoffman was "an old friend" who once directed him in a play at the Public Theater in New York City.