He starred on Broadway in Norman, Is That You?, Two By Two, Pippin (as Pippin), Wild and Wonderful, Grand Hotel, A Christmas Carol at Madison Square Garden, and as The Celebrant in Leonard Bernstein's Mass at The Kennedy Center.
Willison has starred in regional productions of Carousel Carnival!, Two By Two, Oklahoma!, South Pacific, Fiddler on the Roof, On a Clear Day You Can See Forever, Your Own Thing, and as El Gallo in the First International Tour of The Fantasticks in Japan.
Willison has directed productions around the United States, from San Diego's Old Globe Theater to Off-Broadway, and in cabarets and nightclubs.
He conceived and directed Grand Hotel: The 25th Anniversary Reunion Concert starring Liliane Montevecchi and members of the original Broadwat cast, at 54 Below in 2015, conceived, wrote and directed Martin Charnin's The 1977 Annie Christmas TV Special: Live in Concert costarring with Shelly Burch and members of the original Broadway and TV cast at The Cutting Room, and Grand Hotel: The 30th Anniversary Celebration in Concert, benefitting The Actors Fund, directing and costarring with Broadway cast members John Schneider and Karen Akers, and Sachi Parker in 2019.
He came full circle when he conceived, directed and starred as Noah opposite Tony Award winner Karen Ziemba in "Two By Two: The 50th Anniversary Virtual Concert" benefitting The Actors Fund, a streaming production of the musical which premiered on New Year's Day of 2021.