He is editor-in-chief of Tin House magazine and Tin House Books, the former publisher of Oregon Magazine, founder and treasurer of MediAmerica, Inc., and a co-founder of Mother Jones magazine. He serves on the board of directors of the journal New Perspectives Quarterly. His political and social writings have appeared in Oregon Humanities, Tin House, The Nation, The Oregonian, and Oregon Magazine. McCormack's investigative coverage of the Rajneeshee movement was awarded a William Allen White Commendation from the University of Kansas and the City and Regional Magazine Association.
As a political activist, McCormack served as Chair of the Oregon Steering Committee for Gary Hart's 1984 presidential campaign. He was chair of the Democratic Party of Oregon's President's Council and a member of the Obama for President Oregon Finance Committee. Additionally, McCormack sits on the Board of Overseers for Emerson College, and is a co-founder of the Los Angeles-based Liberty Hill Foundation.