Sullivan ran for Congress as a Democrat in New Hampshire's 1st congressional district, which includes Manchester, Portsmouth, and Lake Winnipesaukee.

[3] Sullivan then served as a logistics officer in the U.S. Marine Corps,[4][5] reaching the rank of captain, and her deployments included time in Okinawa, Japan, and Fallujah, Iraq.

[12][13] Since entering the race, Sullivan raised over $1.5 million and was endorsed by EMILY's List, Serve America, New Politics, WithHonor.org, and Vote Vets.

[17] During her campaign, Sullivan was endorsed by Seth Moulton, a fellow Marine Corps veteran and Congressman from Massachusetts.

[20] Sullivan has stated that her top policy priorities include fighting President Trump on matters of national security, ensuring access to affordable healthcare, improving conditions for veterans and military families, and addressing the opioid epidemic.