I used to see him driving around my neighborhood every now and then. Us kids would wave at him as he passed by in his MGTD. This was in Sherman Oaks in the early 60s. Another interesting note is:
One of television's best-kept secrets (that nobody went out of their way to keep secret) is the fact that Peter Graves and James Arness, two of the most iconic leading men of their era, were real-life brothers. Graves, best known as Jim Phelps on Mission: Impossible, exuded cool authority and quiet intellect. Arness, towering and stoic as Marshal Dillon on Gunsmoke, became the face of the TV Western for two decades. Both dominated prime time television, and yet most viewers had no idea that they came from the same family.
Born Peter and James Arness in Minneapolis, the brothers took different professional names and very different paths to stardom. Arness made his film debut in the late 1940s, eventually landing Gunsmoke in 1955 and holding the role for 20 years. Graves, four years younger, built a steady career in film and TV, including stints in science fiction and war dramas, before Mission: Impossible made him a household name in the late '60s.
Despite their enormous fame, the brothers rarely appeared together in public or on screen. They valued their privacy and built careers independent of each other. There were a few exceptions: a single Gunsmoke episode in 1966 that Graves directed, and the occasional red carpet event later in life. Otherwise, the connection remained largely unspoken, becoming an inside fact for TV historians and eagle-eyed fans.