He is the founder and editor of Inside Philanthropy, a digital media site, and Blue Tent Daily, which offers in-depth reporting on progressive organizations and the Democratic Party.
[1] Callahan was a fellow at The Century Foundation from 1994 to 1999;[citation needed] his work area was US foreign policy and international affairs.
[9] A New York Times review of his 2004 book, The Cheating Culture: Why More Americans Are Doing Wrong to Get Ahead, Chris Hedges called Callahan "a new liberal with old values".
[1] The book links the rise in unethical behavior in American society to economic and regulatory trends—particularly growing inequality.
[10] His 2007 book The Moral Center examines how a market-based economy, i.e. capitalism, with its elevation of self-interest, undermines values that both liberals and conservatives care about.
[13] His 2017 book The Givers: Wealth, Power, and Philanthropy in a New Gilded Age looks at top philanthropists such as Michael Bloomberg and Mark Zuckerberg.