Gene Stupnitsky was born in Kyiv, Ukrainian SSR (present-day Kyiv, Ukraine). He graduated from the University of Iowa in 2000.
In 2005, Eisenberg and Stupnitsky joined the staff of the NBC comedy series The Office, where they remained from seasons 2 to 6. In addition to writing, he served as a co-executive producer and directed two episodes with Eisenberg, "Michael Scott Paper Company" and "The Lover". Although he is not credited for directing "The Lover", similarly Eisenberg is not credited for directing "Michael Scott Paper Company", as only one person can be credited with directing the episode. They also directed The Outburst, a webisode series for The Office. He also acted as one of the Vance Refrigeration delivery guys (Leo), along with Eisenberg, present in several episodes of The Office.
In 2013, Eisenberg and Stupnitsky had a busy year in television, and were listed as two of Deadline Hollywood's "Overachievers" of the pilot season. Along with Stephen Merchant, they created, executive produced, and wrote for the HBO series Hello Ladies, which ran for one season and concluded with a feature-length special. That same year, they wrote a pilot for ABC based on the popular BBC series Pulling, in addition to serving as executive producers on the series Trophy Wife, which aired for one season on ABC. They also executive produced the TV series Bad Teacher for CBS, which is based on their original screenplay.
Eisenberg and Stupnitsky have worked together on several screenplays, many of which they have produced as well. Along with Harold Ramis, they wrote the screenplay for Year One, which starred Jack Black and Michael Cera, and was released in 2009. Following that, they wrote and produced the film Bad Teacher, which starred Cameron Diaz and Justin Timberlake. They were to serve as producers of a proposed sequel.
Eisenberg and Stupnitsky wrote a screenplay for Ghostbusters III, but it was not produced.
Stupnitsky made his directorial debut with the 2019 comedy hit Good Boys.