The deal involving two former lottery picks is a chance for both young players to accelerate their careers in fresh environments.
Bucks star Giannis Antetokounmpo said news of the trade was tough, calling Maker his "little brother" and the "heart and soul" of the Bucks.
"He is always going to be my little brother. We are always going to stay in touch," Antetokounmpo said. "It was great having him on the team. Great guy. Amazing energy. Always positive. He was the heart and soul of this team.
"At the end of the day though, it is a business. The NBA is a business, and the NBA is going to look out for the best interest of the team and create a team that is going to try and win a championship. At the end of the day, it is a great opportunity for Thon in Detroit."
Johnson, 22, is averaging 7.5 points and 3.6 rebounds in his fourth NBA season with Detroit. Johnson was the eighth overall pick in the 2015 draft.
Johnson gives the Bucks, who have the NBA's best record at 39-13, another strong wing defender as they prepare for a playoff push. He can become a restricted free agent this summer.
The 7-foot-1 Maker, who is eligible to negotiate a rookie contract extension this offseason, has shown stretches of promise in the league, but he has been in and out of the Bucks' rotation throughout the season. He was part of the team's second unit when Ersan Ilyasova was injured, but forward D.J. Wilson has usurped more of Maker's minutes in recent weeks.
Sources told ESPN in January that Maker, who is averaging 4.7 points and 2.7 rebounds while averaging 11.7 minutes in 35 games this season, had told Bucks management that he would prefer to be traded to a team that would provide a larger role. He'll get an opportunity for playing time with Dwane Casey.
Maker, 21, was the 10th overall pick in the 2016 draft.