Jennings attended Indiana University was a student manager for the Indiana Hoosiers basketball team. While still in school he was hired by the Indiana Pacers as a scout and video coordinator. He joined the Boston Celtics organization in 1986 where he worked as a scout, assistant coach, and Director of Basketball Development. From 1997-2000, Jennings worked in the White House Office as senior assistant in the Office of Cabinet Affairs, director of policy coordination, liaison to the president's initiative on race, and Acting Assistant Attorney General in charge of legislative affairs. Jennings was selected as a White House Fellow in 1997. In May 2000, Jennings was named Vice President of Business Development for Givenation.com, a Non-profit organization run by former Democratic National Committee Chairman Steve Grossman. He later rejoined the Celtics organization as a scout. Jennings completed his degree work on a Masters in Public Administration from Harvard. In 2004, Jennings ran for Indiana's 8th congressional seat as a conservative Democrat opposed to abortion rights and gun control. He defeated Bill Pearman in the Democratic primary but lost to incumbent John Hostettler in the general election. From 2005-2007, Jennings was in charge of the Massachusetts offices of Senator John Kerry. In February 2009, Maine Basketball, LLC, a group Jennings was a partner of, was granted an NBADL expansion franchise. Jennings was named the team's first president and general manager. In 2010, Jennings was named as the first NBA D-League Executive of the Year. He also became a partner in the Red Mango Frozen Yogurt store at the Maine Mall and a development at Thompson’s Point, a project for which he requested and received a $31 million, 30-year tax break from the City of Portland.
City manager, Portland
From 2013-2015 he served as the Assistant City Manager for the City of South Portland, Maine. At the time of his hiring, Dan Boxer, an adjunct professor at the University of Maine School of Law, raised questions about a potential conflict of interest between Jennings's role as a partner in the Thompson's Point project, located in Portland, and his responsibilities as South Portland City Manager, which included attracting businesses that could potentially compete with his Thompson's Point project. Since July 2015, he has been serving as the City Manager for the City of Portland, Maine. As Portland City Manager, he pushed for the closure of the India Street Health Clinic and opposed a $64 million bond to repair the city's four most run down elementary schools, instead supporting a four school plan which would have used a combination of local and State funds. He also had long-running feud with Portland Mayor Ethan Strimling, who supported the school bond and opposed the India St. clinic closure. The feud ended when Strimling's re-election bid failed in 2019.
