Clint is one of those that Star Trek actors who reappears in different episodes and series.
In 1966, he appeared as the powerful but childlike alien Balok in "The Corbomite Maneuver," a season one episode of Star Trek: The Original Series (although not the first episode broadcast, it was the first episode of season one to be produced after the pilot episodes). He briefly reprised the character in 2006 on Comedy Central's roast of William Shatner.
"Past Tense Part II," a Star Trek: Deep Space Nine episode
"Acquisition," a season one episode of Star Trek: Enterprise
"Will You Take My Hand," a season one episode of Star Trek: Discovery[2]
"Under the Cloak of War," a season two episode of Star Trek: Strange New Worlds
As a nod to Howard's prominent place in Star Trek culture, he played a part in Star Trek director J. J. Abrams' series Fringe; in the season one episode, "The Road Not Taken", playing a man who thought he was the son of Sarek of Vulcan. He discussed a fictitious plot by Romulans from the future, much like the one in Abrams' own Star Trek film. (In the next episode, Leonard Nimoy was revealed to be the mysterious character he was discussing.)