Prior to becoming Lt. Governor in 2007, O'Brien spent 16 years as president of the Colorado Children's Campaign, a statewide public policy and advocacy nonprofit organization. Her leadership has produced major statewide policy initiatives that increased funding for schools, created charter schools, expanded early childhood education, increased access to health care for uninsured children, reduced teen smoking and expanded after-school programs.

As lieutenant governor, O'Brien has an ambitious agenda for education, health and wellness, and aerospace issues.  Gov. Ritter appointed Lt. Governor O'Brien to serve as the co-chair of the P-20 Education Council, which oversees education reform and innovation from pre-school to post-secondary education. In its first year, the P-20 Council successfully advocated for expansion of full-day kindergarten and pre-school statewide.

Lt. Gov. O'Brien has also served as Executive Director of the Institute of International Business and Director of Campus Affairs at the University of Colorado, Denver.  She obtained her bachelor of arts at UCLA and PhD at Columbia University.