Koenig portrayed Chekov, a Russian crewman and navigator aboard the Enterprise, in the original Star Trek television series and several films. The character was also described in the supplied reporting as a youthful Russian navigator and the sole Communist-bloc member of the ship's bridge staff.
He later appeared in the science-fiction series Babylon 5, a role noted in reporting by BBC News and The Hollywood Reporter.
The South China Morning Post reported that Koenig died at his home in North Hollywood, Los Angeles, citing a statement from talent agent Zachery McGinnis. The report did not establish an exact calendar date in the supplied material.
The supplied source material does not establish a cause of death. BBC News, The Hollywood Reporter and the South China Morning Post all reported Koenig's death at age 90, while the available evidence provides no further confirmed details about the circumstances.