She was chosen as running mate by Bill Ritter, the Democratic candidate for Governor of Colorado in the 2006 election.

[4][5] Ritter chose not to run for re-election in 2010,[6] and O'Brien also stepped down at the end of her term.

[8] The Denver Post newspaper stated that candidates who promised reform won the majority of local school board elections across Colorado in the November 2013 off-year election, and that O'Brien, as well as her fellow winners for Denver School Board positions, were reform candidates.

[9] As of March 2012[update], O'Brien was a senior fellow at the Piton Foundation, which uses its private funding to develop, manage, and incubate programs to create opportunities for lower-income families in Denver.

[10][full citation needed] In 2013, O'Brien was named President of Get Smart Schools, a Denver-based public education reform group.