Shaffir was born in New York City, and was raised as an Orthodox Jew. His father, born in Iași, Romania, and grandmother were Holocaust survivors. Soon after his birth, his family moved to North Carolina, followed by Maryland. He attended high school in Rockville, Maryland, followed by time at Yeshiva University in New York City. In 1999, Shaffir graduated from University of Maryland.
Shaffir first became known for his viral video series The Amazing Racist In 2013, Shaffir created and produced This Is Not Happening, a stand up comedy web series featuring numerous comedians telling true life stories. The show was initially rejected for television broadcast as Shaffir was too unknown, but it was later picked up by Comedy Central which premiered in January 2015. Later that year, Shaffir performed at the Edinburgh Festival Fringe.
Shaffir appeared in the comedy feature film Keeping Up with the Joneses (2016).
