Clausen said he received a call from Simpsons producer Richard Sakai, who said the show was seeking "a different kind of music." An exact reason for Clausen's firing following a lengthy and successful tenure was not given.
On Twitter, Clausen addressed his firing, writing, "Thank you for all of the support... unfortunately, the news is true…"
Per Variety, some have speculated that Clausen's departure could be part of ongoing cost-cutting measures The Simpsons have enacted over the past few years (even though the show continue to rake in massive profits). Clausen's overhead was especially large as he scored every episode with a 35-piece orchestra. While this set-up was creator Matt Groening's idea from the start of the series, the costs – musicians, studios, orchestrations, other expenses – could run into the millions per year.
Clausen created some of the most memorable television music of the past three decades. He began working on The Simpsons during Season Two, handling background music and cues, and playing a part in countless classic Simpsons songs like "See My Vest," "Stop the Planet of the Apes, I Want to Get Off!" and "Who Needs the Kwik-E-Mart?" At the start of Season Three, Clausen re-arranged Danny Elfman's memorable Simpson's theme song as well.
Clausen won two Emmys for his work on The Simpsons, in 1997 and 1998, and is believed to be the most Emmy-nominated composer of all time, with a total of 30.
Along with working extensively on The Simpsons, Clausen has composed music for numerous TV shows and movies including Ferris Bueller's Day Off, The Naked Gun, Dragnet and, coincidentally, ALF.