Hikaru Sulu was a young human who lived during the 20th and 21st centuries. He was a distant ancestor of 23rd century Starfleet officer Hikaru Sulu.

When the 23rd century Hikaru Sulu traveled back in time from 2286 to 1986, he happened to meet his great-great-grandfather on the streets of San Francisco. The child believed Hikaru Sulu to be his Uncle Akira Sulu, as Hikaru was similar in appearance to this uncle. The 23rd century Hikaru recognized the child almost immediately, having seen pictures of this Hikaru Sulu at various stages in his life. After the meeting was finished, Doctor Leonard McCoy asked Sulu who this child was, and Sulu informed him that Akira was his distant ancestor. (TOS novelization: Star Trek IV: The Voyage Home)