Bitten by the acting bug early in his youth, Koenig studied at the Neighborhood Playhouse in New York where he worked with fellow students James Caan, Elizabeth Ashley, and Dabney Coleman. His stage career spans 30 years and includes stops in New York, Chicago, Los Angeles and many other cities. He appeared in many plays and television shows of the late 1950's and early 1960's, including the Mr. Novak series, and even produced and wrote his own feature film in 1967, I Wish I May. In 1967 he landed the role of Ensign Pavel Chekov in the original Star Trek series.

Koenig has also appeared as Chekov in the first seven of the big screen Star Trek films and currently has a recurring role as Alfred Bester in the TV series Babylon 5. Aside from his role in Star Trek, he has appeared in 40 different TV series and television movies, including Anthony and Cleopatra starring Timothy Dalton and Lynn Redgrave.

A natural writer, Koenig has written for the television shows Family, Matthew Starr, Land of the Lost, Class of '65 and others. His first book, Chekov's Enterprise, which recounts the making of the first Star Trek movie, was published in 1979. He has also written a satiric fantasy novel, Buck Alice and the Actor-Robot, and a three-part comic book series entitled Raver. Koenig wrote and performed a one-character piece entitled You're Never Alone When You're
A Schizophrenic, which was a finalist in the 1996 New York Film Festival Awards.

In a 1997 internet poll of favorite television bad guys, Koenig was the top choice of 12, 000 voters for his role as Alfred Bester on "Babylon 5." He was also voted the favorite guest star on "Babylon 5."

Koenig and his wife Judy Levitt have two children and live in Los Angeles.

Filmography:

1998 Babylon 5 ("Cat and Mouse")
1997 Babylon 5 ("Rising Star")
1997 Drawing Down The Moon
1997 Viva Variety
1997 Babylon 5 ("The Face of the Enemy")
1997 Babylon 5 ("Moments of Transition")
1997 Babylon 5 ("Epiphanies")
1997 Space Cadets
1997 Blonde Justice
1996 Almost Perfect
1996 Babylon 5  ("Ship of Tears")
1996 Babylon 5  ("Dust to Dust")
1996 Babylon 5  ("A Race Through Dark Places")
1996 Babylon 5  ("Mind War")
1994 Star Trek: Generations
1991 Star Trek VI: The Undiscovered Country
1990 The Real Ghostbusters ("Russian About")
1989 Star Trek V: The Final
1989 Moontrap
1986 Star Trek IV: The Voyage Home
1984 Star Trek III: The Search for Spock
1983 Anthony and Cleopatra
1982 Star Trek: The Wrath of Khan
1982 Bring Them Back Alive (The Real World of Frank Buck)
1979 Star Trek: The Motion Picture
1976 Columbo ("Fade in to Murder")
1974 The Men From Shiloh ("Crooked Corner")
1973 Deadly Honeymoon
1973 The Starlost
1973 The Questor Tapes
1972 Ironside ("The Summer Soldier")
1971 Goodbye, Raggedy Ann
1969 Medical Center ("Between Dark and Daylight")
1967 Mannix
1966 Jericho ("Both Ends Against The Riddle")
1965 I Spy ("Sparrowhawk")
1965 Gidgel ("Foreign Policy")
1965 Mr. Novak ("The Firebrand")
1965 Ben Casey ("A Rambling Discourse on Egyptian Water Clocks")
1964 Mr. Novak ("With a Hammer in His Hand, Lord, Lord!")
1962 The Untouchables
1962 Great Adventure TVCombat! ("The Prisoner")
1962 The Norman Vincent Peale Story
1961 Strange Loves