The Klingon captain was portrayed by Mark Lenard, who is better known as Sarek, Spock's father. He was initially offered the role via a phone call from Gene Roddenberry. "I never thought of playing a Klingon," Lenard admitted, "but I said, 'Sure, I would love to.'" The actor found his makeup extremely uncomfortable while playing the part. (Starlog #117, p. 48)
The helmsman was played by stunt actor Joel Kramer; the navigator was one of the unspecified actors listed above.
The Star Trek Customizable Card Game gives the helmsman's name as Karnog. However, he is identified as the ship's science officer. There, he is listed as the science officer of the Amar who tried to analyze the V'ger data.