[citation needed] He portrayed a despicable bookkeeper, Ben Otis, in "The Case of the Angry Dead Man" on Perry Mason.

In 1962, he was cast as Lt. Bronner in the episode "The Handmade Private" of the CBS anthology series GE True, hosted by Jack Webb.

In 1966, Millhollin appeared as an airline ticket seller in the Get Smart episode "The Amazing Harry Hoo".

Also in 1966, he portrayed a bank official in the film The Ghost and Mr. Chicken and a department store manager in the Christmas episode of The Beverly Hillbillies.

[citation needed] He also appeared in the TV series Batman as Alfred Slye, a criminal lawyer for Harry, the evil twin brother to Chandell, portrayed by Liberace.