James was born on the 22nd of January, 1947 in Los Angeles, California, and after he graduated from high school, he attended Los Angeles Harbor Junior College. Halfway through his second year at college, James left in order to enlist in the US Marine Corps and went through recruit training in San Diego, California. Six months later, he graduated and was promoted to Private First Class and continued training at Camp Pendleton. James was only in the Marines for ten months when he deployed to the Republic of Vietnam and it was his actions one month after his twentieth birthday 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. Company F was advancing in dense jungle northwest of Cam Lo in an effort to extract a heavily besieged reconnaissance patrol. Pfc. Anderson's platoon was the lead element and had advanced only about 200 meters when they were brought under extremely intense enemy small-arms and automatic-weapons fire. The platoon reacted swiftly, getting on line as best they could in the thick terrain, and began returning fire. Pfc. Anderson found himself tightly bunched together with the other members of the platoon only 20 meters from the enemy positions. As the firefight continued several of the men were wounded by the deadly enemy assault. Suddenly, an enemy grenade landed in the midst of the marines and rolled alongside Pfc. Anderson's head. Unhesitatingly and with complete disregard for his personal safety, he reached out, grasped the grenade, pulled it to his chest and curled around it as it went off. Although several marines received shrapnel from the grenade, his body absorbed the major force of the explosion. In this singularly heroic act, Pfc. Anderson saved his comrades from serious injury and possible death. His personal heroism, extraordinary valor, and inspirational supreme self-sacrifice reflected great credit upon himself and the Marine Corps and upheld the highest traditions of the U.S. Naval Service. He gallantly gave his life for his country.

James had only been in the Marine Corps for one year and eleven days when he performed these actions and when the Medal of Honor was presented to his parents by the Secretary of the Navy on the 21st of August, 1968, it was the first time a black Marine had ever been awarded the Medal of Honor. The USNS PFC James Anderson Jr, the James Anderson Jr Memorial Park in Carson, California, and Anderson Avenue in Compton, California, are all named in his honor. James Anderson Jr is buried with his mother, Aggiethine, in the Lincoln Memorial Park in Carson, California: Plot L6. His name also appears on the Vietnam Veterans Memorial Wall: Panel 15E, Row 112.