Walter Koenig, the actor forever associated with Pavel Chekov in Star Trek, has died at the age of 90. According to his representative, Koenig died of natural causes at his home in North Hollywood. He was also widely known for portraying Alfred Bester in the acclaimed sci-fi series Babylon 5.

Born in Chicago on September 14, 1936, and raised in Manhattan, Koenig joined Star Trek at the beginning of its second season. He appeared in 36 episodes of the original series and later reprised Chekov in the first seven Star Trek feature films released between 1979 and 1991.

In later interviews, Koenig often recalled how unexpectedly Star Trek changed his life. Initially skeptical of the series, he ultimately became one of its most beloved cast members. The character of Chekov was introduced to appeal to younger viewers and quickly became a fan favorite, generating hundreds of fan letters and making Koenig one of the show’s most recognizable stars.

Beyond Star Trek, Koenig built a diverse career as both an actor and writer. He penned episodes of series including The Powers of Matthew Star, Family, Land of the Lost, and The Incredible Hulk. In the 1990s, he found renewed acclaim as the morally complex telepath Alfred Bester on Babylon 5, a role many fans consider among his finest performances.

Koenig also authored the memoirs Warped Factors: A Neurotic’s Guide to the Universe and Beaming Up and Getting Off, reflecting on his career, life, and experiences in science fiction fandom.

He was married to actress Judy Levitt from 1965 until her death in 2022. The couple’s son, actor Andrew Koenig, died in 2010. He is survived by his daughter, actress and screenwriter Danielle Koenig.

For generations of fans, Walter Koenig remained an integral part of the Star Trek legacy, helping shape one of science fiction’s most enduring franchises while leaving a lasting mark through his work on both Star Trek and Babylon 5.