[1] Sepinwall began writing about television with reviews of NYPD Blue while attending the University of Pennsylvania, which led to his job at The Star-Ledger.

Slate.com said Sepinwall "changed the nature of television criticism" and called him the "acknowledged king of the form" with regard to weekly episode recaps and reviews.

During his time at Uproxx, Sepinwall hosted a podcast called TV Avalanche with fellow television critic Brian Grubb.

His father, Jerry, was a psychopharmacologist,[3] and his mother, Harriet, is a former professor of social studies education at the College of St. Elizabeth in Morristown, New Jersey.

Sepinwall was later critical of his writings from this period, describing it as full of "misspellings, bad grammar and, even worse, observations that make me cringe".

[8] Slate.com writer Josh Levin described Sepinwall's week-to-week, post-episode reviews of The Sopranos as "a new form" that combined episode recaps with analyses of the show's subtexts and hidden meanings.

[10] After 14 years with The Star-Ledger, Sepinwall left the newspaper in 2010 for a job at the entertainment journalism website HitFix, where he would review as many as 15 television shows each week.

[11] In 2010, Slate.com writer Josh Levin said Sepinwall "changed the nature of television criticism" and called him the "acknowledged king of the form" with regard to weekly episode recaps and reviews.

[14] During his appearance in a charity fundraiser on The George Lucas Talk Show, Sepinwall agreed to review The Star Wars Holiday Special, which he had never seen.