Colt, who designed over 50 Broadway shows, was nominated for three Tony Awards in 1956, for The Lark, Phoenix '55, and Pipe Dream, winning for the last-named show. He was also nominated for L'il Abner and The Sleeping Prince in 1957, and for Greenwillow in 1960.
Among the many other shows he designed were On the Town, Guys and Dolls, The Golden Apple, Fanny, Wildcat, Destry Rides Again, Sugar, and First Impressions. He also remained the designer for the Off-Broadway revue Forbidden Broadway up until his death.
Colt donated approximately 3,000 of his sketches to the Museum of the City of the New York, which hosted a small exhibition of his work last year.