Zaslow guest starred on a number of other television shows and soap operas, including Barnaby Jones and Law & Order. In the episode "The Man Trap," the series' September 8, 1966 premiere of Star Trek, he played Crewman Darnell, the first Starship Enterprise crew member to be killed off. The incident sparked the first diagnosis of the now-famous line: "He's dead, Jim," by Enterprise crew-member Dr. Leonard McCoy (DeForest Kelley). He also appeared as Jordan in the episode "I, Mudd". He also costarred in the 1977 feature film You Light Up My Life, and appeared in the 1979 sci-fi movie Meteor.