The greatest piece of evidence supporting the Boston Celtics’ reputation as one of the most successful teams in NBA history is their 17 NBA titles, which is a record. Even though it takes a unique and exceptionally clever company to accomplish such feats in the NBA, errors have been made throughout the years, whether via trades or the draft. The Boston Celtics are just one NBA club, and none of them are flawless.

Picked by the Boston Celtics: Bennie Swain, eighth overall

Hal Greer, the 14th overall pick, is a better available pick.

When Bob Cousy and Sam Jones comprised the Boston Celtics’ backcourt going into the 1958–59 campaign, it was evident that the team was set at the guard position. They chose Texas Southern’s 6’8″ power forward Bennie Swain as their choice because of this. Unfortunately for Boston, Swain would only play in the NBA for one season—averaging 4.6 points and 4.5 rebounds per game—before hanging up his boots. Hey, at least he finished it on a positive note that same season, when the Celtics started their eight-year NBA title winning streak.

Even though Cousy and Jones secured their place in the starting lineup, one cannot not but wonder what may have happened if the Celtics had chosen guard Hal Greer, who fell to the Syracuse Nationals in the 14th round. With the team, Greer would go on to enjoy a Hall of Fame career that included ten All-Star selections, seven selections to the All-NBA Team, and an NBA title in 1967. The Celtics dynasty might have lasted far longer if Boston had chosen to start Jones at small forward and go with Cousy and Greer in their backcourt.

Celtics of Boston Tom Boswell, the 17th overall pick, was chosen.

Gus Williams, the 20th overall pick, is the better available pick.

It would be almost twenty years before the Celtics made a disastrous draft selection. In 1975, the Celtics selected 6’9″ power forward Tom Boswell from the University of South Carolina with their first-round pick. In his first campaign, Boswell had a difficult time breaking into the Celtics rotation, appearing in just 35 games for an average of fewer than 8.0 minutes per game as the team went on to win the NBA championship in 1976. Boswell would stay in Boston for two more seasons, scoring 5.9 points and pulling down 3.9 rebounds a contest.

Before opting to play abroad in Italy in 1981, Boswell would go on to play 97 games in Denver and 61 games in Utah. In a brief comeback to the Jazz in 1983–84, he played in 38 games but only scored 1.9 points per contest on average.

The Golden State Warriors selected future NBA champion and All-Star Gus Williams just three picks after Boswell was selected by the Celtics. Although Williams is well-known for his time with the Seattle SuperSonics, where he was an NBA champion in 1979 and a two-time All-Star, he would be a decent fit with the Warriors. Williams averaged 20.3 points, 6.0 assists, and 2.3 steals per game while playing with the SuperSonics for six seasons. His inclusion among the 1980s Celtics would have brought  greater intensity to their ten-year rivalry with the Lakers.
Celtics of Boston Norm Cook was chosen as the 16th overall pick.

Alex English, the 23rd overall pick, is the better available pick.

In 1976, the Boston Celtics had the opportunity to select top offensive players in the summer draft, even after winning the NBA title. The Celtics selected Norm Cook, a small forward from the University of Kansas, with their 16th overall pick. Between 1977 and 1978, Cook participated in 27 NBA games for the Celtics and Nuggets, averaging 2.4 points and 1.1 rebounds per contest. After the 1978 season, he decided to hang up his shoes for good.