Broderick, who currently stars in Broadway's Nice Work If You Can Get It, will play a neurotic new friend of Phil's (Ty Burrell) on the series' fourth season.
"Modern Family" also features Ariel Winter, Eric Stonestreet, Julie Bowen, Sofia Vergara, Sarah Hyland, Ed O'Neill, Aubrey Anderson-Emmons, Nolan Gould, Rico Rodriguez and Jesse Tyler Ferguson.
Broderick won Tony Awards for his performances in Brighton Beach Memoirs and How to Succeed in Business Without Really Trying and was nominated for his performance in The Producers. He has also been seen on Broadway in The Philanthropist, The Odd Couple, Taller Than a Dwarf and Night Must Fall, among others.
The fourth season of "Modern Family" will premiere Sept. 26 at 9 PM on ABC. Visit ABC.go.com/ModernFamily.