The Bucks signed the swingman Friday, bringing him back after he spent the 2019-20 season with them.
Matthews, who played in high school in Madison, Wisconsin, and collegiately at Marquette, started 67 games for the Bucks two seasons ago. He spent last season with the Los Angeles Lakers.
"Wesley is a proven veteran whose shooting, defense and experience will help us," Bucks general manager Jon Horst said in a statement. "He is familiar with Coach Bud's system and our team. We're excited to have him back with us."
Matthews has averaged 12.6 points in 849 games over 12 seasons.
The Bucks also waived rookie guard Georgios Kalaitzakis.