During the remainder of the 60s, Cassidy had another ultra-smooth role as Hollywood leading man Byron Prong in Fade Out-Fade In (1964), was egotistical columnist Max Mencken in the comic strip spoof It’s A Bird, It’s A Plane, It’s Superman (1966), and played Irishman Phineas Flynn in the Civil War musical Maggie Flynn (1968). In the title role of the latter show was Shirley Jones, the former star of films such as Oklahoma!, Carousel and The Music Man, who was Cassidy’s second wife. Cassidy himself also appeared in a number of films, notably as John Barrymore in W.C. Fields And Me and as Damon Runyon in The Private Files Of J. Edgar Hoover. After his Broadway career declined, he worked in regional theatre, both straight and musical, and appeared on television and in nightclubs. He died at the age of 49 in a fire at his Los Angeles apartment. Three of his sons, Patrick Cassidy and Shaun Cassidy (from his marriage to Shirley Jones), along with David Cassidy (from his earlier marriage to Evelyn Ward), are also in showbusiness.