Moulton was the 19th Democratic candidate to join the field.
Out of the running: In an interview with The New York Times, Moulton said, "I think it's evident that this is now a three-way race between Biden, Warren and Sanders, and really it's a debate about how far left the party should go."
Full Name: Seth Wilbur Moulton
Date of birth: Oct. 24, 1978
Hometown: Salem, Massachusetts
Family: Wife Elizabeth and daughter, Emmy.
Education: He earned a dual master's degrees in business and public administration from Harvard University in 2011 and a bachelor of arts in physics, Harvard University (2001)
What he does now: In 2014, Moulton unseated John Tierney, a nine-term incumbent, to win Massachusetts' 6th Congressional District and has been re-elected twice since. He also serves on the House Armed Services Committee.
What he used to do: After graduation from Harvard University, Moulton enlisted in the U.S. Marine Corps in 2001 at 22 years old. As an infantry officer, he served four tours of duty in Iraq, two as a special assistant to then-Gen. David Petraeus.
Key life/career moments:
According to Moulton's personal LinkedIn profile, he was an intern for Goldman Sachs in 2010 and in 2011 he was the president of Eastern Healthcare Partners, Inc, a medical company aiming to "address the burden of obesity and diabetes."
Before his successful run for Congress, he was a managing director for the Texas Central Railway, a private company working to build a 240-mile high-speed rail line that would connect Dallas and Houston.
He currently serves on the House Armed Services Committee, the House Budget Committee and is also one of many co-sponsors of the Bipartisan Background Checks Act, which is the first major gun safety policy to be passed in the House since 1994.
Where he stands on some of the issues:
In an interview with ABC's "This Week," Moulton released his "National Service Education Guarantee" which aims to encourage young Americans to serve their country. This plan allocates money for those who serve in the military, AmeriCorps, FEMA Corps, or a new organization Moulton would establish, the "Federal Green Corps."
Moulton is calling for a public healthcare option, to lower prescription drug prices, and for coverage of pre-existing conditions. The public option aims for lower costs compared to plans under the Affordable Care Act, according to his campaign website.
Through the second fundraising quarter, Moulton raised $1.2 million with an additional $684,750 transferred to his campaign. He ranked 17th in funds raised among 2020 candidates, directly behind Marianne Williamson's $1.5 million and Tulsi Gabbard at $1.6 million.
What you might not know about him:
Moulton's parent's, Tom and Lynn, didn't know he was awarded the Bronze Star for valor, and the Navy and Marine Corps Commendation Medal for valor until The Boston Globe listed his awards in 2014. He was awarded for his "courageous battlefield presence under intense enemy fire," and "aggressive, from-the-front leadership," according to the military citations obtained by the newspaper.
Moulton collaborated with his Iraqi translator, Mohammed Harba, to create "Moulton and Mohammed," a television news show that aired twice a week in Iraq.
He was also prominently featured in "No End in Sight," a 2007 Oscar-nominated documentary.
In 2015, Moulton was named one of the "50 Most Beautiful" people in Washington by The Hill.
Moulton played the organ in high school, according to Phillips Academy classmate Tom Balamaci.
Bobby Gehlen contributed to this report.