In the late 80s, Shaiman's work writing special music for NBC's "Saturday Night Live" (for which he earned an Emmy nomination in 1987) introduced him to Billy Crystal, who helped him get the job adapting music for Rob Reiner's "When Harry Met Sally" (1989). He co-wrote two of the picture's songs and co-produced Harry Connick Jr.'s Grammy-winning, gold album of the same name, garnering a Grammy nomination himself as arranger. He solidified his association with Reiner by composing his first film score for the director's "Misery" (1990) and has since scored all or part of Reiner's "A Few Good Men" (1992), "North" (1994), "The American President" (1995), "The Ghosts of Mississippi" (1996) and "The Story of Us" (1999). As for Crystal, he tapped the composer to score "City Slickers" (1991), "Mr. Saturday Night" (1992), "City Slickers II: The Legend of Curly's Gold" (1994), "Forget Paris" (1995) and "My Giant" (1998), all starring the comic actor. Shaiman earned an Emmy nomination as Crystal's musical director for "The 63rd Annual Academy Awards" (1991) and pocketed the award the following year for his contributions to Crystal's hosting of "The 64th Annual Academy Awards", not to mention teaming with him on several TV specials.
Shaiman has also enjoyed a long and fruitful collaboration with producer Scott Rudin, who first hired him to score Barry Sonnenfeld's "The Addams Family" (1991), followed quickly by "Sister Act" (1992) and the sequels "Addams Family Values" and "Sister Act 2: Back in the Habit" (both 1993). They also teamed on "In & Out" (1997), the first gay-themed picture that the openly homosexual Shaiman scored, as well as Albert Brooks' "Mother" (1996) and two of the first five films for which Shaiman would receive Oscar nominations. He was first honored for the jaunty original song "A Wink and a Smile", used in Nora Ephron's smash "Sleepless in Seattle" (1993), then garnered nominations for the scores of "The American President", "The First Wives Club" (produced by Rudin) and "Patch Adams" (1998). His fifth nod came as co-writer (with director Trey Parker) of the irreverent "Blame Canada" from "South Park: Bigger, Longer & Uncut" (1999, executive produced by Rudin).
Shaiman made his onscreen acting debut as one of the news theme writers in "Broadcast News" (1987) and had cameos as a Conductor in "The Addams Family" and as Lucky Zinberg in "Mr. Saturday Night". Otherwise, he has played the Piano Player (or Pianist or Piano Accompanist) in four films ("Scenes from a Mall", "Hot Shots!" 1991, "Heart and Souls" 1993, "North"). Although quite happy with the genres in which he currently has worked, he has expressed his dislike for the fact that he has become typecast as a composer of theatrical and comedic scores yet still has to audition to sell his music for films of that ilk.
Shaiman has worked as a musical director and arranger for a long list of performers, including Rosemary Clooney, Lauryn Hill, Patti LuPone, Luther Vandross and Raquel Welch. He has stated that he is most proud to have musical directed "Commitment to Life VII", which featured Tom Cruise, Tom Hanks, Whitney Houston, Angela Lansbury, Liza Minnelli, Barbra Streisand, Bruce Springsteen and Elizabeth Taylor and which raised over $5 million for AIDS Project L.A. (APLA).