Bart received his second Tony Award nomination for playing Carmen Ghia in the original production of The Producers and his third for his performance as "Doc" Brown in Back to the Future: The Musical.
Additional theatre credits include Jonathan in the Alan Menken/Tim Rice musical King David, Harlequin in Triumph of Love, Snoopy in the Broadway revival of You're a Good Man, Charlie Brown (for which he won the Drama Desk Award and a Tony), Carmen Ghia and later Leo Bloom in The Producers (earning Drama Desk and Tony nominations), and The Frogs at Lincoln Center, which reunited him with fellow Producers star Nathan Lane and Susan Stroman.
He became widely known to viewers with his portrayal of George Williams, the unhinged homicidal pharmacist in love with Bree Van de Kamp (Marcia Cross), on Desperate Housewives, which earned him a SAG Award.
He was featured in the 2004 remake of The Stepford Wives with Nicole Kidman, Matthew Broderick, Bette Midler, Christopher Walken and Glenn Close, and in The Producers (2005), in which he reprised his role of "common-law assistant" Carmen Ghia.
He reprised the role alongside former Broadway co-stars Shuler Hensley and Cory English in the United States national tour that launched in September 2009.
[citation needed] Brad Oscar and Bart reprised their roles as Max Bialystock and Leo Bloom, respectively, in a production of The Producers at Starlight Theatre in Kansas City, Missouri.
[18] In 2018, Bart was cast in the main role of Judge Wilson on the Freeform drama series Good Trouble, the spin-off of The Fosters.
[20] After playing the role at the Manchester Opera House and West End's Adelphi Theatre, he reprised the part in the Broadway production.