He defeated Heather Wilson, and will succeed Democrat Jeff Bingaman, who is retiring after 30 years.
Heinrich has represented the Albuquerque area's 1st Congressional District since 2009, when he took over a seat held by Wilson for five terms. Wilson didn't seek re-election in 2008 and ran unsuccessfully for the GOP Senate nomination after Republican Pete Domenici decided to retire.
Both parties viewed the race between Heinrich and Wilson as important in the national battle for control of the Senate. However, polling during the campaign showed that Wilson struggled to attract crossover support among Democrats, which is critical in a state where Republicans account for only one-third of voters.
Heinrich portrayed himself during the Senate campaign as a defender of the middle class and safety net programs. Wilson emphasized the economy and the need to reduce the nation's budget deficit but vowed to protect programs such as Social Security.
Heinrich, 41, has quickly climbed the ranks of New Mexico politics. He moved to the state in 1995 to take a job at a federal research facility after earning an engineering degree from the University of Missouri. He later started a public affairs consulting business and in 2003 won a seat on the Albuquerque City Council.
Heinrich grew up in Missouri, where his father was a utility company lineman and his mother was a factory worker.
Wilson, 51, is an Air Force Academy graduate whose Scottish grandfather served in the Royal Air Force in World War I. She won election to Congress in 1998 after serving in the cabinet of former Gov. Gary Johnson as the administrator of the state's juvenile justice agency.
After leaving Congress, Wilson returned to New Mexico and worked as a defense industry consultant.