Mann's first attempt won him an Oscar, for adapting his 1959 "Playhouse 90" script "Judgment at Nuremberg" for the screen in 1961. He went on to adapt his teleplay "A Child is Waiting" (1962) for the big screen as well, and furnished screenplays for Vittorio De Sica's "The Condemned of Altona" (1962), Stanley Kramer's "Ship of Fools" (1965), "The Detective" (1968), "Report to the Commissioner" (1975) and "War and Love" (1985).
But TV provided Mann with steadier employment. He wrote and produced the 1973 TV-movie "The Marcus-Nelson Murders" (CBS), which then had a five-year run as the series "Kojak", starring Telly Savalas. In 1985, Mann was credited as "creator" on the first of seven "Kojak" TV movies, which ran through 1990 on both CBS and ABC. He served as executive producer on the pilot and series "Medical Story" (NBC, 1975-76) and the CBS miniseries "Sinatra" (1992); and he was both producer and screenwriter for the miniseries "King" (NBC, 1978, which he also directed), the NBC pilot "Skag" (1980), the CBS miniseries "The Atlanta Child Murders" (1985) and the HBO movie "Teamster Boss: The Jackie Presser Story" (1992). Mann shared Emmy Awards for co-writing and co-producing the HBO movie "Murderers Among Us: The Simon Wiesenthal Story" (1989). While he was in the process of writing and producing the 1995 HBO movie "Indictment: The McMartin Trial", Mann's house burned down, destroying many unpublished scripts and mementos. Mann felt that someone opposed to the McMartin telefilm was responsible.