"When somebody is 19 years old, they're gonna do what they're gonna do, just like we did," the actor told Extra.
Smith also revealed he recently reached out to Bieber, who is a friend of his son, Jaden.
"For me, the most important thing was for him to know anytime he can just call and I'll come, whatever happens," Smith says. "At that age, that's what you need, to know you can do what you're gonna do, but you have somewhere you can go, where you can find safety."
Smith added, "It's hugely important to support artists, young artists specifically. There is a war against that kind of artistry, that kind of creation."
Just last month, the Men in Black 3 star's wife, Jada Pinkett Smith, shared her husband's sentiment when she posted a message on Facebook slamming the "bullying" the media often directs at Bieber and other young celebs.