On Wednesday, the Ypsilanti, Mich., standout became the first signee in the Class of 2014 for the Cardinals. Johnson signed his national letter-of-intent on Wednesday morning and sent it into the school.
"Jaylen is excited and ready to be a Cardinal," Johnson's mother, Janetta, said. "I think I was more nervous than he was, but I am excited as well. We believe he made the right decision and I know he feels that way.
"Louisville is the best place for him and he's excited to get there."
Pitino isn't expected to talk about the class until Thursday, but the 6-foot-9, 200-pound star is set to be one of the centerpieces of the class.
Johnson is ranked as the No. 62 player in the '14 class by Scout.com, checking in as the No. 14 power forward in the country.
"Johnson has a lot of potential," Scout.com national analyst Evan Daniels said. "He's young for his grade and appears to be somewhat of a late bloomer. He's mobile, athletic and fairly skilled for his size.
"He could be the steal of their class."
Johnson picked up a scholarship offer from U of L in June after an unofficial visit and committed to the Cardinals over Michigan State, Oregon, Iowa, Texas, North Carolina State among several others.
Johnson's mother, who played at Wisconsin and led the nation in blocked shots for one season, called Pitino "a Hall of Famer for a reason," and noted after watching him with his team that "it's easy to see why he's won two national titles."
The mother said her son already feels like family with the staff and team and is "so excited to get there and start playing," with the Cardinals.
"One thing I can say about them is they have been like family since day one," she said. "Now, it's just going to be official and I don't believe they will change. We have talked to them and had a chance to spend time with them and I just believe in the end it was the best fit for Jay. Coach Pitino will do the best he can do to pull the best out of Jaylen and all of his other players, he's going to be great for him.
"A man of his stature, coach Pitino could let his assistants coach or recruit but that's not him. He's so involved with everything. I believe in him and the whole staff and Jaylen believes in him and the staff."