Before the season even began, Cummings’ bumped heads with San Diego's now-infamous owner, Donald Sterling.

As a result of that, and other tense exchanges, Cummings’ agent tried to negotiate a one-year deal to get his client away from the Clippers as soon as possible, however, the two sides eventually agreed to a four-year contract during the preseason.

[1] In his inaugural 1982–83 season, he won the NBA Rookie of the Year Award after putting up 23.7 points and 10.4 rebounds per game.

[4] The following season, Cummings and now hall of fame-enshrined teammate Sidney Moncrief led the Bucks to a 57–25 record and an Eastern Conference Finals appearance.

[6] During that season's postseason run, on April 22, 1986, Cummings scored 23 points, grabbed 11 rebounds, and recorded a playoffs career-high 3 blocks in the final game of a 3–0 first round sweep of the New Jersey Nets.

[8][9] However, in a familiar pattern for the 1980s Bucks, they would ultimately fail to reach the NBA Finals, this time losing to the Boston Celtics.

On January 9, 1987, Cummings grabbed a career high 24 rebounds, alongside scoring 28 points, in a 100–92 loss to the Washington Bullets.

[10] On January 16, 1987, in what was arguably the best game of his career, Cummings recorded a triple double with 39 points, 15 rebounds, and 10 assists, while adding a career-high 6 steals in a 124–122 loss versus the Dallas Mavericks.

[16] That season, Cummings set a career high in points scored in a single game, with 52 in a 129–95 win over the Charlotte Hornets.

He contributed as a role player helping the Sonics reach the Western Conference Semi-finals where they lost to the Houston Rockets in 7 games.

Before the lockout ending in 1999, he was traded by the Knicks along with John Starks and Chris Mills to the Golden State Warriors for Latrell Sprewell.

Cummings wanted to be a professional hockey player growing up, and had not attempted playing competitive basketball until an unexpected high school growth-spurt.

[20] On April 4, 1985, Cummings sang the national anthem in Milwaukee before playing in a home game versus the Detroit Pistons.