Landesberg was a member of the cast of the 1974 CBS situation comedy Paul Sand in Friends and Lovers. He made guest appearances on the TV shows The Tonight Show, The Rockford Files, Law & Order, Saturday Night Live, The Golden Girls, Ghost Whisperer, That '70s Show and Everybody Hates Chris. He starred in Starz's original show Head Case as Dr. Myron Finkelstein. He appeared in the motion pictures Wild Hogs, Leader of the Band, and Forgetting Sarah Marshall.