Fellows is the creator and executive producer of Nickelodeon's Ned's Declassified School Survival Guide, Kids WB!, Teletoon, Cartoon Network and Netflix's Johnny Test, and Nickelodeon's hit Kid's Choice Award-winning TV series Big Time Rush.

Fellows had been previously working as a staff writer and executive producer on The Fairly OddParents.

His earlier writing credits also include episodes of Weinerville (where he performed Zip, Louie, and Professor Phosphate), U to U, All That, 100 Deeds for Eddie McDowd, Doug,[citation needed] and the unaired pilot for I Don't Think So.

[1] In November 2006, the series won the Global Entertainment Award for best kids' programming of the millennium, in a ceremony held in Copenhagen, Denmark.

The series concluded on July 25, 2013, after four years on television, although the band continued to perform for a few months before going on a hiatus.