He worked as a manager with the Young Men's Christian Association (YMCA), and served as President of the Canadian Council for International Cooperation.
[7] For the next five years, Patten served as President and CEO of the Children's Hospital of Eastern Ontario (CHEO) Foundation, doing extensive fund-raising work for the organization.
He attempted to mobilize a campaign for the party's leadership in 1996, but failed in this effort and subsequently supported Dwight Duncan.
[10] In the 1999 provincial election, Patten was re-elected over Progressive Conservative Ray Kostuch and New Democrat Elisabeth Arnold.
[12] On 14 March 2007, Patten announced he would not seek re-election in the upcoming election, preferring to focus on work with the CHEO Foundation.