Democratic Party politician and New York City's forty-second Comptroller. After serving two terms as Comptroller (from 2002-2009), he launched two unsuccessful campaigns (in 2009 and 2013) for the office of Mayor of New York City.
After graduating from Tufts University in Massachusetts, he worked in the office of fellow New York Democrat Fred Richmond.
During the late 1990s, while holding various New York City political offices, he also held an executive position with the Keyspan Energy natural gas company.
He was raised in Brooklyn, New York by New York State Senator William C. Thompson, Sr. and New York City schoolteacher Elaine Thompson. His marriage to Elsie McCabe Thompson resulted in a daughter named Jennifer.
New York Mayor Rudolph Giuliani endorsed Thompson's successful campaign for President of the New York City Board of Education.