James was interested in becoming a fighter pilot in WWII, but he was too tall (6'7"), for the cockpit so he joined the Army. He was shot in the leg during a battle and was sent to a military hospital back in the states. He received an honorable discharge in 1945 and had a Bronze Star and a Purple Heart. His leg bothered him throughout his life and jumping on and off horses was very difficult for him.
When he was discharged from the Army, he enrolled in college but then quit shortly after and hitchhiked to Hollywood. He spent 10 years doing mostly bit parts in over 20 movies and was also on an episode of: The Lone Ranger, before landing the leading role on Gunsmoke in 1955. It was John Wayne who recommended Arness for the part. When the show ended in 1975, Arness took a break for a year and then starred on the television show: How the West Was Won which ran for three years. There were also a couple of Gunsmoke movies after the show ended.
On a personal level, Arness was married to actress Virginia Chapman for 12 years. They had a daughter and son together. He adopted Virginia’s son (Craig), from a previous marriage and he went on to become a photographer for National Geographic. Sadly, Virginia died at 56 years of age from a drug overdose. His daughter Jenny, who was a child actor on Gunsmoke, died of a suicide when she was just 25 years old. His other son, Rolf, is still alive and is best known for winning the World Surfing Championship in Australia. Eighteen years after his divorce from Virginia, he married Janet Surtees whom he was married to for 33 years until his death at the age of 88 in 2011.