The episode was seen by an estimated 3.26 million household viewers and gained a 1.4/4 ratings share among adults aged 18–49, according to Nielsen Media Research.
In the cold open, the squad members steal Scully's smelly shoes from him while he's asleep and blow them up outside, only for the explosion to make the smell worse.
In its original American broadcast, "Old School" was seen by an estimated 3.26 million household viewers and gained a 1.4/4 ratings share among adults aged 18–49, according to Nielsen Media Research.
With these ratings, Brooklyn Nine-Nine was the second most watched show on FOX for the night, beating Dads and The Mindy Project but behind New Girl, fourth on its timeslot and tenth for the night in the 18-49 demographics, behind New Girl, The Goldbergs, The Biggest Loser, Person of Interest, Agents of S.H.I.E.L.D., Chicago Fire, NCIS: Los Angeles, NCIS, and The Voice.
The tone was mostly salty, with just the right amount of sweet – what with Peralta defending Holt's honor and appreciating Santiago's abnormally warm butt.
The former didn't play a large part in the episode, but he did what he could in the subtle moments when the viewer is supposed to be paying attention to the joke.
"[5] Alan Sepinwall of HitFix wrote, "Couple that with a B-story about Terry and Charles coaching Rosa about her courtroom demeanor that used all three characters well (and continued the Schur/Goor trend from 'Parks and Rec' of funny montages of people trying on strange outfits) and didn't overstay its welcome, and you've got another promising outing for the rookie comedy.
"[6] Aaron Channon of Paste gave the episode an 8.8 out of 10 and wrote, "All of this was wrapped inside an episode that included great hangover humor ('Ughhh, my whole body has drymouth'), advancement of the Rosa-Charles dynamic, which could warrant another recap by itself, tiny nuggets of inside-joke goodness and a not-unsubtle Die Hard reference (again highlighting the writers' supreme understanding of the genre).
It was Brooklyn Nine-Nine's best episode yet and the one that elevates it from an enjoyable new fall sitcom to must-watch TV (as much as any network television show can invoke such an imperative).