Ulman worked on campaigns to elect Bill Clinton in 1996, Maryland Governor Parris Glendening in 1998, and Kathleen Kennedy Townsend in 2002. Ulman first ran for political office in 2002, when he sought the district 4 County Council seat that was being vacated by Mary Lorsung. Ulman won the Democratic primary by 50 votes and beat Republican opponent, Joan Lancos, in the general election. Ulman served a four-year term as a Council member in Howard County.

While attending college at University of Maryland, College Park, Ulman studied government and politics and interned at the White House. He received a bachelor’s in 1997 and was admitted to Georgetown Law School. During law school, he served as director of the Maryland Board of Public Works determining state school construction allocations He received a J.D. in 2001 and was admitted to the Maryland State Bar Association. He initially joined his father’s law firm taking cases on a contract basis before entering local politics in 2002.

In 2006, Ulman ran for county executive against Republican Party opponent, Christopher Merdon, and Independent candidate, C. Stephen Wallis. A major theme of Ulman’s campaign was his claim he played a role in preventing the closure of Columbia’s Merriweather Post Pavilion. Ulman won in the general election with 52% of the vote and was sworn in on December 4, 2006 at age 32, becoming the youngest person in Maryland to be elected as county executive. During his tenure as county executive, Ulman served as chairman of the Baltimore Regional Transportation Board and the Baltimore Metropolitan Council. He was also on the board of directors of the Maryland Association of Counties and County Executives of America.

On June 3, 2013, Ulman announced that he would be running in 2014 for lieutenant governor of Maryland as the running mate of gubernatorial candidate and incumbent lieutenant governor, Anthony G. Brown. After being defeated by the Republican ticket of Larry Hogan and Boyd Rutherford, Ulman left public office in December 2014 at the end of his term as Howard County Executive and founded a consulting firm, Margrave Strategies.