Private First Class Jansen was a Light Weapons Infantryman with the 35th Infantry Regiment, 25th Infantry Division. He was Killed in Action while fighting the enemy in North Korea on 26 November 1951.

Jansen was awarded the Purple Heart, the Combat Infantryman's Badge, the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the Korean Presidential Unit Citation and the Republic of Korea War Service Medal.