LOS ANGELES — Walter Koenig, whose portrayal of the youthful Russian navigator Pavel Chekov helped make the bridge of the USS Enterprise a symbol of international cooperation, has died. He was 90.

Koenig died Sunday at his North Hollywood home, with his daughter, Danielle, and his niece beside him, according to his representative. His death was attributed to natural causes. tmz.com

He joined “Star Trek” in its second season in 1967, becoming a familiar presence alongside William Shatner’s Capt. James T. Kirk, Leonard Nimoy’s Spock and George Takei’s Hikaru Sulu.

With his youthful appearance, Russian accent and enthusiasm for claiming Russian credit for seemingly everything, Chekov supplied both humor and a hopeful message. At the height of the Cold War, a Russian officer was serving alongside Americans aboard a ship exploring humanity’s shared future.

The original NBC series ended in 1969, but Chekov’s voyage continued for decades.

Koenig appeared in all six original-cast “Star Trek” films, beginning with “Star Trek: The Motion Picture” in 1979. He also returned for “Star Trek Generations” in 1994, bringing his total to seven theatrical films — one more than the six cited in some initial accounts of his career. startrek.com

His performances ranged from the disturbing encounter with Khan’s mind-controlling creatures in “Star Trek II: The Wrath of Khan” to the comic misunderstandings of “Star Trek IV: The Voyage Home.”

The role made him recognizable worldwide, but another science-fiction series gave him an opportunity to play someone considerably less reassuring.

On “Babylon 5,” Koenig portrayed Alfred Bester, a calculating telepathic officer whose composed manner often concealed ruthless intentions. The recurring part demonstrated a darker side of an actor many viewers knew primarily as an earnest member of the Enterprise crew.

His final contribution to the official “Star Trek” television franchise came in 2023, when he voiced President Anton Chekov, Pavel’s son, in “Star Trek: Picard.” ew.com

Koenig also made his mark as a writer. Although Chekov was omitted from “Star Trek: The Animated Series” because of budget constraints, Koenig wrote its episode “The Infinite Vulcan.” His books included the behind-the-scenes account “Chekov’s Enterprise” and the autobiography “Warped Factors.”

Born Sept. 14, 1936, in Chicago to Jewish immigrant parents, Koenig studied psychology at UCLA before pursuing acting and training at New York’s Neighborhood Playhouse. He began building television credits in the early 1960s before landing the role that would define his public life.

He married actress Judy Levitt in 1965. She died in 2022. Their son, actor Andrew Koenig, died in 2010. Their daughter, Danielle, survives him. people.com

Hollywood recognized Koenig with a Walk of Fame star on Sept. 10, 2012. Fellow “Star Trek” performers attended the ceremony, celebrating a career that had extended far beyond the original series’ brief network run. startrek.com

Takei remembered that career through the lens of a friendship lasting nearly six decades. Koenig had served as best man when Takei married Brad Altman in 2008.

“Walter was more than Chekov,” Takei wrote in a tribute, remembering his friend as a writer, teacher and thoughtful companion.

Koenig remained closely associated with the fans who helped sustain “Star Trek” long after its cancellation. In announcing his death, his representative emphasized the warmth and appreciation he brought to convention appearances.

For generations of viewers, he remained the young navigator at his station: alert, enthusiastic and ready for whatever lay beyond the next star.