James Arness obituary. Gunsmoke actor James Arness has died, leaving behind a letter he wanted released upon his death. He was 88 years old. James Arness, best known for his role as a towering Dodge City lawman in Gunsmoke, died at home in his sleep Friday. He was 88 years old. Arness left behind a touching letter to his fans with the intention it be posted to his website after his death.