He was known for playing Dr. McCarty in the third and fourth season of the American western television series The Life and Legend of Wyatt Earp.
[2] Cassady appeared in the films Up Front (1951), starring David Wayne and Tom Ewell; Meet Danny Wilson (1952), starring Frank Sinatra, Shelley Winters and Alex Nicol; Footsteps in the Night (1957), starring Wild Bill Elliott; Man's Favorite Sport?
(1964), starring Rock Hudson and Paula Prentiss and Not with My Wife, You Don't!
(1966), starring Tony Curtis, Virna Lisi and George C. Scott.
He guest-starred in television programs including Sergeant Preston of the Yukon, State Trooper, Death Valley Days, Johnny Midnight, Highway Patrol, The Wild Wild West and Harbor Command.