Halpern wanted to create a counter-force to the growing influence of the many right-wing think tanks such as The Heritage Foundation and establish a multi-issue organization that would focus on progressive policy development and advocacy.

David Callahan, a fellow at the Century Foundation, and Stephen B. Heintz, vice president of the EastWest Institute, joined Halpern in helping to found Demos.

In this first year, Demos' work focused on solving economic inequities and increasing civic participation by developing a more inclusive democracy.

In 2016, Demos fired blogger Matt Bruenig after he called the Center for American Progress's president Neera Tanden a scumbag.

[7][8] Demos was part of a settlement in a lawsuit, filed in 2005, alleging Ohio Secretary of State Ken Blackwell, Governor Bob Taft, and their predecessors failed to protect the fundamental rights of eligible Ohio voters to cast a meaningful ballot, as required by the Equal Protection and Due Process Clauses of the Fourteenth Amendment to the United States Constitution.