He was a co-founder of Polaris Project, a Washington, D.C.-based nonprofit organization that combats human trafficking and modern slavery.

At CPAC, Ellerman served as the Executive Director and worked to support individual victims of police abuse.

He assisted in successfully advocating for the creation of the first civilian review board for law enforcement in the state of Rhode Island.

[1][3] In 2002, during his senior year at Brown, Ellerman co-founded Polaris Project with Katherine Chon after reading an article in a local paper about a fake massage business, the conditions of which were close to slavery.

[4] Located in the United States, Polaris Project works to address and combat all forms of human trafficking, while providing programs and services to help all victims throughout the country.