Born in Moline, Illinois to Elaine (d.2015) and Felix Kuberski (d. 1983), Steve was raised with siblings Susan, Kathy, Carol and Brian.

Moline played in Wharton Field House, a former home of the early NBA's Tri-Cities Blackhawks, who were coached by a young Red Auerbach.

[2] As a senior in 1964–1965, Kuberski, under new Coach Herb Thompson, led Moline to the Illinois High School Association Tournament Elite Eight as the Maroons finished 25–3.

Kuberski was suspended for receiving financial assistance of US$35 per month from a slush fund established illegally by the school's athletic department.

[6][7] Kuberski, and teammates Rich Jones and Ron Dunlap, along with two others, had been suspended indefinitely while Illinois did an internal investigation during the 1966–1967 Illini season.

[2] In 1968–1969, Kuberski averaged 23.0 points, 10.1 rebounds and 1.6 assists for the Bradley Braves, as the team finished 14–12 under Coach Joe Stowell in the Missouri Valley Conference.

Kuberski signed with the Celtics and GM Red Auerbach in September 1969, foregoing a potential final season of collegiate eligibility.

As in the previous season, the Celtics defeated the Atlanta Hawks (4–2) in the playoffs before losing to the New York Knicks 4–3 in the Eastern Conference Finals.

The Celtics defeated the Milwaukee Bucks with Kareem Abdul-Jabbar, Oscar Robertson and Bob Dandridge in the NBA Finals.

After the Celtics claimed Kuberski off waivers, they immediately put him into the starting lineup and won 14 of their next 16 games, en route to the Atlantic Division and an NBA title.

The Celtics defeated Kuberski's former team, the Buffalo Braves, 4–2 and then the Cleveland Cavaliers 4–2 en route to the NBA Finals.

In the NBA Finals, the Celtics defeated the Phoenix Suns 4–2, as Kuberski averaged 5.5 points and 3.5 rebounds in the series, earning a second championship ring.

[20] Overall, Kuberski played nine National Basketball Association seasons for the Boston Celtics, Milwaukee Bucks, and Buffalo Braves, averaging 5.5 points and 3.8 rebounds per game.

Back then you were just one piece of the puzzle and that’s the way Red Auerbach played the game.”[25] Kuberski and his wife Diane married in 1967, after they met when she was a cheerleader at Moline High School.

[25] Steve Kuberski founded his own company in the New England area in 1982, making lockers for schools, country clubs, restaurants and warehouse products.