While directing a show for a Greenwich Village club he met songwriter and composer Marc Shaiman, and the two became collaborators and professional partners.
While Shaiman wrote for television shows, including Saturday Night Live, Wittman directed concerts for such artists as Bette Midler, Christine Ebersole, Raquel Welch, Dame Edna Everage, and Lypsinka, among others.
[3] Shaiman and Wittman worked on Catch Me If You Can, a musical adaptation of the 2002 Steven Spielberg film, together with Terrence McNally.
In 2013, Wittman and Marc Shaiman co-wrote the score for Bombshell, a musical about Marilyn Monroe within the context of the NBC television show Smash.
In 2021, Wittman and Shaiman wrote a song entitled "Save the City" for the Marvel Cinematic Universe (MCU) in-universe Broadway production, titled Rogers: The Musical featured in the first episode of Hawkeye, "Never Meet Your Heroes".