Smith was fined $50,000 by the NBA for "recurring instances of unsportsmanlike conduct" after he untied the shoelaces of Dallas Mavericks forward Shawn Marion and attempted to do the same to Detroit Pistons center Greg Monroe.
In addition to the fine, Knicks coach Mike Woodson benched Smith in a game against the Miami Heat.
Smith returned to the court Saturday against the Philadelphia 76ers to help lead the team to a 102-92 win, USA Today reported.
After the game, Smith reflected on his punishment.
"It's the worst feeling in the world, when somebody literally just takes the game away from you," Smith said, "especially something you love, you've been doing it your whole life, this is all you know, you know nothing else. It's the worst feeling in the world."
"I'm still trying to find myself, trying to find the right way to be a professional and stuff like that," he added. "There's a short span we get to play this game. I can't be selfish with it. I've got to think team-first."