Don Grady was a trouble-making teen rebel until My Three Sons changed his attitude

In the years just before Don Grady joined My Three Sons as the middle brother Robbie, the child star appeared on many Westerns, including twice on The Rifleman.

For his second Rifleman episode, "Heller," Grady plays a young boy who plots with his sister to kill their abusive father, using Lucas McCain for a ride into town to get what they need to carry off the dark scheme. It's a role that showed a fiercer side to the teen idol.

In this role, Grady is ready to do anything to keep his father from hurting his mother and sister, and if you've seen this episode, you know playing this particularly troubled TV teen was a far cry from the kind of drama that Grady would get into on My Three Sons with his most famous TV siblings.

By 1960, Grady actually was more like this Rifleman teen, though. He said he was ready to throw his life away without thinking clearly about the consequences of some of the trouble he started getting into.

Rising up as a Mouseketeer on The Mickey Mouse Club, Grady's fame came quickly, but by the age of 16, as he told The News Palladium in 1964, he was already worried his acting career had fizzled out.

"I became introspective, if I'm not flattering myself," Grady said. He was downtrodden remembering this low period in his life that he said led him to get involved with a new crew of rebellious high school friends.

He said if My Three Sons didn't come along when it did and snatch him out of this bad boy high school circle, that desire beginning to well in him to participate in shenanigans might have boiled over into real acting out, with real consequences, as he remembered it did for his friends.

"I would go to school, and then I'd come home and do my homework, and then I'd hang around with the guys," Grady said. "I never got into serious trouble, but later, after I got into My Three Sons, some of those old pals got into real trouble. I might have, too — who knows?"

Good thing he was more into acting than acting out. Grady said it probably saved him from juvenile delinquency.

By 19, Grady had matured a lot and he had a new best friend: his mom.

In an interview with The Capital Times, Grady is described as a "deadly serious youngster who is the man of his house," whose relationship with his mom was "exceptionally close."

In fact, they became so close, they took a giant leap together, both working toward their pilot’s licenses and learning to fly to even greater heights in life as best friends.

As for the rest of his private life, Grady confirmed that right then he had "little time for friends" and only went on dates occasionally with a steady girlfriend whose identity remained a secret. He said when they went out, they liked to go out for dinner, then catch a foreign flick or attend a lively debate at UCLA.

Like he was taught a life lesson ripped from My Three Sons, it seems Grady gained confidence by walking in Robbie's shoes through his arc on the show, and this had a positive effect on how he was steering his personal life and career. This was the moment he was taking on more responsibilities: going to college and becoming a writer, on top of acting as his most famous character Robbie Douglas. He had a lot going on, and no time for shenanigans!

Although in 1964, Grady wasn't ready to leave his mom's home, by 1970, he was done with My Three Sons, explaining to The Los Angeles Times that part of the problem of playing Robbie was that doing the role, he felt locked into the tender age of 15. As we all know now, that was such a complex time for him in real life.

Grady said the character of Robbie "was crystallized when I was about 15, and it's not a part, it's me I'm playing, the writers have developed the character out of me — but the way I was at 15!"

Luckily to help him grow into the man Grady really wanted to become, he had good role models, people on the set of My Three Sons who he considered the "father figures I needed" to steer him right: his TV dad Fred MacMurray and producers Don Fedderson and Ed Hartmann.