Raymond was born in Fitzgerald, Georgia, on the 13th of January, 1915. When he graduated from Atlanta Technical High School in 1933, he went on to attend the Georgia Institute of Technology. Raymond graduated with a Bachelor of Science degree in chemical engineering in 1938 and since he was a member of their Reserve Officer Training Corps, he was also commissioned upon graduation. He resigned this commission on the 27th of June, 1938, in order to accept an appointment as a Second Lieutenant in the Marine Corps.

Shortly after joining, Raymond attended and completed the Marine Officers' Basic School at the Philadelphia Navy Yard in May of 1939 and was then assigned to the USS Portland which was stationed in the Pacific for a year. Shortly after being promoted to First Lieutenant, he was the battery executive officer with the 1st Antiaircraft Machine Gun Battery, 1st Marin Division and they were moved to the Marine Corps Barracks in North Carolina. The following year Raymond was promoted to Captain in February of 1942 and then became the battery commander.

Raymond was deployed to the Pacific during World War 2 and spent most of his time in Guadalcanal. He also served in the Eastern New Guinea, Cape Gloucester, and Peleliu campaigns. His actions as a Major in command of the 1st Battalion, 1st Marines at Peleliu earned him the Navy Cross. Raymond was promoted to Lieutenant Colonel in October of 1944 and when he returned to the States in November of 1944, he became a tactical inspector at the Marine Corps Schools in Quantico. After the War, he returned to the Pacific but this time as the 1st Provisional Marine Brigade's assistant chief of staff until August of 1948. He was Instructor-Inspector of the 9th Marine Corps Reserve Infantry Battalion in Chicago when he deployed to Korea in August of 1950. It was Raymond's actions during the Battle of the Chosin Reservoir that would earn him the Medal of Honor. The citation reads:

For conspicuous gallantry and intrepidity at the risk of his life above and beyond the call of duty as commanding officer of the 1st Battalion, in action against enemy aggressor forces. Although keenly aware that the operation involved breaking through a surrounding enemy and advancing 8 miles along primitive icy trails in the bitter cold with every passage disputed by a savage and determined foe, Lt. Col. Davis boldly led his Battalion into the attack in a daring attempt to relieve a beleaguered rifle company and to seize, hold, and defend a vital mountain pass controlling the only route available for two Marine Regiments in danger of being cut off by numerically superior hostile forces during their re-deployment to the port of Hungnam. When the Battalion immediately encountered strong opposition from entrenched enemy forces commanding high ground in the path of the advance, he promptly spearheaded his unit in a fierce attack up the steep, ice-covered slopes in the face of withering fire and, personally leading the assault groups in a hand-to-hand encounter, drove the hostile troops from their positions, rested his men, and reconnoitered the area under enemy fire to determine the best route for continuing the mission. Always in the thick of the fighting Lt. Col. Davis led his Battalion over 3 successive ridges in the deep snow in continuous attacks against the enemy and, constantly inspiring and encouraging his men throughout the night, brought his unit to a point within 1,500 yards of the surrounded rifle company by daybreak. Although knocked to the ground when a shell fragment struck his helmet and 2 bullets pierced his clothing, he arose and fought his way forward at the head of his men until he reached the isolated Marines. On the following morning, he bravely led his Battalion in securing the vital mountain pass from a strongly entrenched and numerically superior hostile force, carrying all his wounded with him, including 22 litter cases and numerous ambulatory patients. Despite repeated savage and heavy assaults by the enemy, he stubbornly held the vital terrain until the two Regiments of the Division had deployed through the pass and, on the morning of 4 December, led his Battalion into Hagaru-ri intact. By his superb leadership, outstanding courage, and brilliant tactical ability, Lt. Col. Davis was directly instrumental in saving the beleaguered rifle company from complete annihilation and enabled the two Marine Regiments to escape possible destruction. His valiant devotion to duty and unyielding fighting spirit in the face of almost insurmountable odds enhance and sustain the highest traditions of the U.S. Naval Service.

Raymond's time in Korea also earned him two Silver Stars, the Legion of Merit with V device, and a Bronze Star. He received the Medal of Honor from President Truman in a ceremony at the White House on the 24th of November, 1952. For the next seven years, Raymond held varying office jobs in Virginia and Washington DC and was also promoted to Colonel. He completed the National War College in June of 1960 and was then assigned to the US European Command in Paris, France until July of 1963. While on his way back to the States, he was promoted to Brigadier General and he went on to serve as an assistant division commander of the 3rd Marine Division, Fleet Marine Force in Okinawa.

By the time the Vietnam War had began, Raymond was a Major General and was deployed as the Deputy Commanding General of the Provisional Corps in South Vietnam, before becoming the commanding General of the 3rd Marine Division. His actions while in command earned him the Navy Distinguished Service Medal and three Republic of Vietnam Gallantry Crosses from the South Vietnam government.

Back in the States, Raymond's career would see no more warfighting and would be promoted to Lieutenant General on the 1st of July, 1970, and then General on the 12th of March, 1971. His last assignment was as Assistant Commandant of the Marine Corps and he retired from the Marine Corps on the 31st of March, 1972 after thirty-three years of service.

In retirement, Raymond became an executive with the Georgia Camber of Commerce. He served as the chairman of an advisory board to the Korean War Veterans Memorial. In September of 2002, Raymond was part of a small group organized by the Defense Department that was allowed by North Korea to visit the Western side of the Chosin Reservoir. This was the first time Americans had been allowed to visit the mountainous area that they had fought in almost a half century earlier.

On the 3rd of September, 2003, Raymond Gilbert Davis died from a heart attack at the age of 88. His funeral detail and honor guard were personally commanded by the Commandant of the Marine Corps (at the time), General Hagee. He is buried in the Forest Lawn Memorial Gardens in College Park, Georgia, and his wife Willa joined him seven years later.