Brock Turner, the former Stanford University student and champion swimmer who was found guilty in March 2016 of sexually assaulting an unconscious woman on campus, is appealing his conviction.

A 172-page brief filed on Friday by Mr. Turner’s lawyer, Eric Multhaup, said Mr. Turner did not get a fair trial for several reasons, including the exclusion of testimony by character witnesses who spoke of his swimming career and his performance in school and attested to his honesty, the appeal said.

About 60 pages focus heavily on how intoxicated the victim, known as Emily Doe, was on the night of the attack.

Mr. Multhaup declined to offer a comment beyond the brief.

“Brock Turner received a fair trial and was justly convicted,” Jeff Rosen, the Santa Clara County district attorney, said in a statement on Saturday. “His conviction will be upheld. Nothing can ever roll back Emily Doe’s legacy of raising the world’s awareness about sexual assault.”