He attended Regis High School and Harvard University, where he studied Chinese and Japanese history and politics.
He failed all his Japanese-language courses, but was active as a writer, editor and cartoonist at The Harvard Lampoon, where he was twice elected a vice president, and somehow managed to graduate with honors.
Dan started his television career as a writer at Saturday Night Live, where he was a frequent collaborator with Adam Sandler and Chris Farley.
Club called McGrath's "Boy-Scoutz 'n the Hood" episode "pretty much comic gold from start to finish" and "utterly fantastic" and said it "features one of the greatest, most true-to-life depictions of a bender/drug binge in television history".
He also worked on Gravity Falls, The PJs, and a nearly decade-long stint at King of the Hill, contributing episodes like "Full Metal Dust Jacket" and "The Minh Who Knew Too Much".