The award for best supporting actor went to Troy Kotsur for his role in “CODA.” He is the first deaf male actor ever to be nominated and to win an Oscar. Mr. Kotsur broke similar barriers throughout the season as he was honored by almost every organization that nominated him, including the Screen Actors Guild and Critics’ Choice Awards.

His Oscar milestone puts him in familiar company: His “CODA” co-star Marlee Matlin was the first deaf Oscar nominee and winner. She won best actress in 1987 for “Children of a Lesser God.”

Mr. Kotsur took the stage to applause and waving hands in the audience, which indicates applause in American sign language.

Mr. Kotsur handed his Oscar to presenter Youn Yuh-jung so he could sign his acceptance speech, which was spoken by an interpreter. He thanked “CODA” director Sian Heder as a bridge between the deaf and hearing worlds.

Mr. Kotsur grew up in Arizona in a hearing family. He thanked his father, who he described as “the best signer in our family,” but who was left unable to sign after being paralyzed neck down in a car accident. “Dad, I learned so much from you. I’ll always love you. You are my hero.”

Mr. Kotsur also dedicated his win to the deaf community, the CODA community, and the disabled community: “This is our moment.”

In his signed acceptance speech, Mr. Kotsur dedicated his win to the deaf community, the CODA community, and the disabled community: “This is our moment.”

In “CODA,” which stands for child of deaf adults, Mr. Kotsur plays Frank Rossi, whose deafness is a disadvantage in his family’s fishing trade. He and his wife (Ms. Matlin) butt heads with their hearing teen daughter (Emilia Jones), who chafes at her duties as the family’s interpreter and pursues her ambition to sing.

As the tough and grizzled Frank, Mr. Kotsur is “as plausible an on-screen fisherman who’s ever off-loaded a net full of flounder,” wrote Wall Street Journal critic John Anderson. Mr. Kotsur used the versatility of sign language to enhance Frank’s dialogue, which is sometimes salty enough to push the limits on the movie’s PG-13 rating.

Mr. Kotsur, 53, is a seasoned actor, especially on stage with the National Theatre of the Deaf and Deaf West Theatre. But he was about to quit acting before getting “CODA,” he has said in interviews, because of a lack of roles available to deaf actors in Hollywood.