Before gaining fame in films, Moriarty worked for several years as an actor at the
Guthrie Theater in Minneapolis. In 1973, Moriarty was cast as the egocentric baseball player
Henry Wiggen in
Bang the Drum Slowly opposite
Robert De Niro as a slow-witted,
terminally ill catcher. In the same year, Moriarty starred in a TV movie adaptation of
Tennessee Williams'
The Glass Menagerie with
Katharine Hepburn. Coincidentally, the film also featured
Sam Waterston, who later replaced Moriarty as the Executive Assistant District Attorney on
Law & Order. Moriarty's role in
The Glass Menagerie (as Jim, the Gentleman Caller; Waterston played the son Tom) won him an
Emmy Award for Best Supporting Actor. He had a small part in
The Last Detail, which was nominated for several
Academy Awards. In 1974, Moriarty starred as rookie detective Bo Lockley in the acclaimed police drama
Report to the Commissioner. Moriarty won a
Tony Award in 1974 for his performance in the play
Find Your Way Home. His career on the screen was slow to develop, while his theatre career was flourishing. He played the lead character in
Report to the Commissioner and had a significant role in ''
Who'll Stop the Rain. He starred as the German SS officer Erik Dorf in the television miniseries Holocaust, which earned him another Emmy. Through the 1980s, Moriarty starred in such Larry Cohen movies as Q, The Stuff, It's Alive III: Island of the Alive, and A Return to Salem's Lot (much later, he appeared in Pale Rider and The Hanoi Hilton, as well as the Masters of Horror episode "Pick Me Up", directed by Cohen. In 1986, he starred in the fantasy science-fiction movie Troll'', playing the role of Harry Potter, Sr. (unrelated to the
Harry Potter series). In 1989, Moriarty starred in the
HBO production
Tailspin: Behind the Korean Airliner Tragedy, which dramatized the
Soviet Union's shoot-down of
Korean Air Lines flight 007 in 1983. He portrayed
U.S. Air Force Major Hank Daniels, who was largely ignored (if not ridiculed) for showing how the ill-fated airliner had strayed off course into air space known by the Soviets to be used by U.S. Air Force electronic surveillance planes as they approached Soviet air space. From 1990 to 1994, Moriarty starred as Executive Assistant District Attorney
Ben Stone on
Law & Order. He left the show in 1994, alleging that his departure was a result of his threatening a lawsuit against then-Attorney General
Janet Reno, who had cited
Law & Order as offensively violent. Moriarty criticized Reno's comment and claimed that she wanted to censor not only shows such as
Law & Order, but also such fare as
Murder, She Wrote. He later accused
Law & Order executive producer
Dick Wolf of not taking his concerns seriously and claimed that Wolf and other network executives were "caving in" to Reno's "demands" on the issue of TV violence. On September 20, 1994, on
The Howard Stern Show, he made an offer to NBC, claiming that he would return to his role on the show if Wolf was fired. Moriarty published a full-page advertisement in a Hollywood trade magazine calling upon fellow artists to stand up with him against attempts to censor TV show content. He subsequently wrote and published
The Gift of Stern Angels, his account of this time in his life. In the fictional
Law & Order universe, Ben Stone resigns from the D.A.'s office in 1994 after a witness in one of his cases is murdered. The February 7, 2018, episode of
Law & Order: Special Victims Unit shows Sam Waterston's character,
Jack McCoy, delivering a eulogy at Stone's funeral. Wolf and others working on
Law & Order contradict Moriarty's account of how he left the series. On November 18, 1993, Moriarty and Wolf, along with other television executives, met with Reno to dissuade her from supporting any law that would censor the show. Wolf said that Moriarty overreacted to any effect the law was likely to have on the show.
Law & Order producers claim they were forced to remove Moriarty from the series because of "erratic behavior", an example of which reportedly happened during the filming of the episode "Breeder", when, according to the episode's director Arthur Forney, Moriarty began muttering to himself with a vacant look in his eyes, was unable to deliver his lines with a straight face, and had to be taken to a doctor. Series and network officials deny any connection between his departure and Janet Reno. Wolf also denies that the show has become less violent, graphic, or controversial since 1994. Moriarty acted in
The Last Detail,
Courage Under Fire,
Along Came a Spider,
Shiloh,
Emily of New Moon, and
James Dean, for which he won his third Emmy. In 2007, he debuted his first feature-length film as screenwriter and performed the role of a man who thinks he is
Adolf Hitler in
Hitler Meets Christ. ==Other ventures==