After graduating in 2009, he moved to New York and began working as a research associate in the Heroin & Opiates Addiction lab of Columbia University's Department of Psychiatry.
In 2012, Warheit was drawing cartoons on post-it notes in his lab office, and posting them daily to his Tumblr blog,[5] which led to Above Average Productions ordering an animated web series based on his post-it drawings.
The pilot script that Warheit wrote ended up in the hands of Seth Meyers who was looking for writers for his Hulu series, The Awesomes, and hired Warheit to write and direct for the show.
A month later, Meyers was named the new host of Late Night, and brought on Warheit as a staff writer.
In 2019, Warheit appeared in the psychological thriller Joker and romantic comedy A Rainy Day in New York.