Garelick was born in New York City. He attended Yale University and graduated with degrees in Film and Theater. He is of Jewish background.

Garelick subsequently produced the American High films Looks That Kill, The Ultimate Playlist of Noise, and Plan B. In August 2020, Garelick made his American High directorial debut with The Binge, a spoof of The Purge set in a world in which drugs and alcohol are illegal, except for one day. A sequel to the film is set to begin production in January 2022. Four additional American High movies are currently in post-production.

In 2020, Garelick was named one of The Hollywood Reporter's Top Innovators in 2020 for his role in creating American High. In order to have the area around the A.V. Zogg School zoned for filming by the city of Liverpool, American High also offered a trade school, in addition to its use as a film studio. Each American High production employs about 10 students from local colleges like Syracuse University, Ithaca College, and Le Moyne College.

In August 2020, Garelick said that American High would relocate, citing high expenditures and code-compliance "confusion."However, as of December 2021, American High is still in operation at A.V. Zogg School.

Filmography:

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Year	Film	Director	Writer	Producer	Notes
2006	The Break-Up		Yes	Yes
2009	The Hangover		Yes		Uncredited re-write
2015	The Wedding Ringer	Yes	Yes	Yes	Directoral debut
2018	Family			Yes
2018	Banana Split			Yes
2019	Big Time Adolescence			Yes
2020	Holly Slept Over			Yes
2020	Looks That Kill			Yes
2020	The Binge	Yes		Yes
2021	The Ultimate Playlist of Noise			Yes
2021	Plan B			Yes
2023	Murder Mystery 2	Yes			Post-production