Hardy, 27, remains a free agent after completing a one-year deal with the Dallas Cowboys, which followed a five-year stint with the Panthers.
Carolina opted not to pursue Hardy in free agency last offseason after the defensive end missed all but one game in 2014 while facing domestic violence charges.
"He's a good guy," Johnson told ESPN.com this week. "He just makes bad decisions. I just hope he gets out there and finds a place so he can really prove his talent and show what he's really all about instead of giving interviews to people about the situation.
"He should just move on and throw that all the way back, move forward and take it day by day. Don't do interviews."
Hardy's domestic violence case was dismissed in February 2015 when accuser Nicole Holder declined to cooperate with the district attorney's office, which said it had "reliable information" that Holder and Hardy reached a civil settlement.
Johnson supported Hardy throughout, and nothing Hardy said this week in an interview with ESPN's Adam Schefter changed that.
Johnson said he believed Hardy when he told Schefter, "I've never put my hand on any woman."
"That's my friend," Johnson said. "I ain't got no other choice but to believe him. Whatever he's telling me, I'm going to believe that because I've got no other choice.
"But at the same time, you was involved in the incident. So you have to man up to all the situations that you was involved in. So instead of criticizing all the stuff, just man up to all the situation and move on. Face the facts. This was something three years ago, so why are we still talking about it?"
Hardy played five years at the right end spot, opposite Johnson, after the Panthers selected him in the sixth round of the 2010 draft.
Team owner Jerry Richardson made the decision not to pursue Hardy in free agency last season after paying him $13.1 million in 2014 as the team's franchise player. "We do the right things," Richardson told ESPN.com last spring when explaining his decision to move on from Hardy.
Some of Hardy's Carolina teammates, such as Johnson, continued to support him.
Former Carolina wide receiver Steve Smith did not, however, after watching Hardy deny his involvement in domestic violence. Smith, now a member of the Baltimore Ravens, responded on Twitter after watching the Schefter interview:
Johnson had this advice for Smith, whose mother was a victim of domestic violence.
"I would tell Smitty don't add on with the criticism of everybody else," he said. "Try to help him out. If you ain't going to help him out or bring him up, don't say nothing at all. Don't add to the criticism of everybody else."
Johnson and Hardy keep in touch via text. Johnson's advice to Hardy is to "just stay as low as possible" and hope for another chance.
"Stay humble," Johnson said. "... Don't add on to the fire. Be humble about it. Accept what you did. Accept the situation and move on and get back to where you want to be instead of keep revisiting what happened."