During the Guadalcanal campaign, Munro was assigned to Naval Operating Base Cactus at Lunga Point, where small boat operations were coordinated. At the Second Battle of the Matanikauin September 1942, he led the extrication of a force of Marines whose position had been overrun by Japanese forces. He died of a gunshot wound at age 22 while using the Higgins boat that he was piloting to shield a landing craft filled with Marines from Japanese fire.

Several ships, buildings, and monuments have been dedicated to Munro, and a street in his hometown is named after him. The anniversary of his death is annually observed in Cle Elum and at Coast Guard Training Center Cape May. His grave has been designated a historical site by Washington state. He is the namesake of the Douglas A. Munro Coast Guard Headquarters Building, Munro Hall at the U.S. Coast Guard Academy,^[4] the “Douglas Munro March”, the Navy League‘s Douglas A. Munro Award, the Coast Guard Foundation‘s Douglas Munro Scholarship Fund, and the Veterans of Foreign Wars‘ Douglas Munro–Robert H. Brooks Post. He is the only non-Marine to have his name enshrined on the Wall of Heroes of the National Museum of the Marine Corps.