He is perhaps best known as Lt. Howard Hunter on Hill Street Blues or as Doogie’s dad on Doogie Howser, M.D. James B. Sikking died Saturday of complications from dementia at the age of 90, according to Variety.

Sikking was born in Los Angeles and graduated in theater arts from UCLA. His film and television career stretches back over sixty years, with his earliest screen appearances occurring in 1955’s Five Guns West and a 1961 episode of Perry Mason. He would go on to appear in shows such as The Outer Limits and Mission: Impossible and in films such as The Terminal Man and The Pelican Brief.

Star Trek fans know Sikking as Captain Lawrence H. Styles, commander of the USS Excelsior in Star Trek III: The Search for Spock. (Styles’ full name is revealed, according to Memory Alpha, on a commemoration plaque for the Excelsior in the Star Trek: Picard episode, “The Star Gazer.”)

According to Deadline, his publicist, Cynthia Snyder, said, “In a remarkable career, Sikking’s wonderfully exciting face gave us drama, comedy, tragedy and hilarious farse. His talent, integrity and imagination intrigued and delighted audiences.”

Please join us in offering our condolences to the friends and family of James Barrie Sikking.