Williams was selected by the New York Knicks in the first round of the 1977 NBA draft. After a quiet first season, he improved his effectiveness on the court, averaging 20.9 ppg, 5 rpg, and 6.2 apg during his third season and becoming the team captain during his fourth season. During his time with the Knicks, he reached the NBA Playoffs twice. After four seasons with the Knicks, Williams was traded to the New Jersey Nets on October 25, 1981, in exchange for Maurice Lucas. With the Nets, Williams averaged 20.4 ppg, 4 rpg, and 6 apg. On April 17, 1982, Williams scored 52 points in a game against the Detroit Pistons, for the highest-scoring game of his career, and the highest in Nets history until he was surpassed by Deron Williams' 57-point game on March 4, 2012. Williams eventually helped the Nets reach the 1982 NBA Playoffs where he averaged 17 ppg, 6 rpg, and 7 apg. However, they ended up being eliminated by the Washington Bullets in the first round. On June 29, 1982, the Nets traded Williams to the Kansas City Kings for Phil Ford. After one season, they traded him back to the New York Knicks for Billy Knight and an amount of cash. He reached the playoffs once again with the Knicks, averaging 11.2 ppg and 8 apg. In the middle of the 1984–85 season, Williams signed as a free agent with the Boston Celtics, in exchange for two future draft picks. During this year, he had the chance to play with Larry Bird and Kevin McHale. With Boston, he reached the playoffs one last time. This time, the Celtics reached the Finals, but were eliminated by the Los Angeles Lakers. Before the 1985–86 season, Williams signed with the Los Angeles Clippers, with Boston receiving a future draft pick as compensation. The Clippers, however, waived him before the season began. Williams eventually signed with the Atlanta Hawks. After 19 games, he was waived by the Hawks, but signed with the San Antonio Spurs later. After 23 games, he was also waived by the Spurs and claimed by the Nets. Williams played the remainder of the season with them and remained with the team during the next season, after which he retired. Williams ended with a career average of 15.5 ppg, 5.8 apg, and 3.6 rpg.
NBA career statistics
Regular season
Playoffs
Post-NBA career
After his retirement, Williams struggled financially, eventually filing for bankruptcy in 1994, which led him to lose his home and family. Williams decided to apply early for his NBA pension of $200,000. After he received it, he moved to Florida, where he fell victim to a real estate scam that worsened his financial condition. After that, Williams worked various jobs like groundskeeper at a golf course in Central Florida, apartment complex maintenance man, part-time girls basketball coach, and bakery worker, among others. During that time, he also received grants from the NBA Retired Players Association, totaling $10,000, which couldn't help his situation. According to a profile published in The Boston Globe in July 2010, he was unemployed and homeless, living inside a car in Pompano Beach, Florida. Williams spent his time fishing at the Hillboro Inlet Park in Pompano Beach, to help maintain himself. In November 2010, Williams' luck began to turn around as he took a job in Mount Vernon, New York, working for the city's Recreation Department as a "Recreation Specialist." Mount Vernon Mayor Clinton I. Young, Jr. was instrumental in bringing Williams back to his hometown. Williams was also helped by Linda Crawford, a nurse and a friend from his NBA days. Williams married Linda Crawford in August 2011.
