Who was captain of star ship enterprise James kirk or Alan Shepard?

Captain James T. Kirk, portrayed by William Shatner in the original "Star Trek" series, is the fictional captain of the starship USS Enterprise. Alan Shepard, on the other hand, was a real-life astronaut and the first American in space, but he was not associated with the Enterprise. Therefore, Kirk is the correct answer when it comes to the captain of the USS Enterprise.