Fred Christensen was born on October 17, 1921, in Watertown, Massachusetts. He enlisted in the Aviation Cadet Program of the U.S. Army Air Forces on February 4, 1942, and was commissioned a 2d Lt and awarded his pilot wings at Napier Field, Alabama, on December 13, 1942. After completing P-47 Thunderbolt training, he was assigned to the 62nd Fighter Squadron of the 56th Fighter Group in England in August 1943. Between November 1943 and July 1944, Capt Christensen flew 107 combat missions and was credited with destroying 21.5 enemy aircraft in aerial combat plus 2 damaged. He left active duty on November 20, 1946, and joined the Massachusetts Air National Guard on November 15, 1947. Col Christensen commanded the 102nd Tactical Fighter Group of the Massachusetts ANG from November 1947 to August 30, 1961, when he left the National Guard and entered the Air Force Reserve. He retired from the reserves on October 17, 1981, and died on April 4, 2006. Fred Christensen is buried at the Massachusetts National Cemetery in Bourne, Massachusetts.

His Silver Star Citation reads:

For gallantry in action, while piloting a P-47 fighter aircraft on a bomber escort mission over Germany, 20 February 1944. Just after the squadron which he was flying reached the limit of its range, Lieutenant Christensen observed a ME-109 preparing to attack the bombers. He immediately pursued the enemy plane, forcing it to break off the attack and dive for cover. Climbing to rejoin his flight he saw a DO-217 and another member of the flight destroyed it, despite a withering hail of fire from the hostile plane. Critically low on fuel and ammunition, Lieutenant Christensen again headed for home only to spot a JU-88 below him. Though still deep in enemy territory, he dove for the plane and holding his fire until dead astern, scored direct hits on both engines. As the enemy aircraft burst into flames and spun to the ground, Lieutenant Christensen set his course for England. His gallantry, skill and disregard for personal safety in zealously seeking out the enemy and destroying him contributed in a large measure to the safety of the bomber formation.