Hansen was selected by the
Chicago Bulls in the third round (37th overall) of the
1976 NBA draft. He instead opted to sign with the
Cinzano Milano in Italy's second-tier
Serie A2 Basket, where he averaged 19.2 points per game during the 1976–77 season. He was selected by the
Los Angeles Lakers in the seventh round (151st overall) of the
1977 NBA draft. He decided to remain in Italy, where he played for the
Cinzano Milano in the 1977–78 season. On September 14, 1978, he signed as a
free agent with the
Chicago Bulls. He was waived on October 10. On December 15 of that year, he was signed by the
Seattle SuperSonics to a 10-day contract. He later signed a contract for the balance of the season. He appeared in 15 games as a backup behind
Jack Sikma, averaging 5.1 points and 3.9 rebounds. He was part of the franchise's title season and became the first Canadian to appear on an NBA championship roster. He also holds the distinction as being the first Denmark-born player in the NBA. On January 18, 1979, he was released make room for
Center Dennis Awtrey. On April 12, 1979, he was signed by the
Kansas City Kings. He was released on September 26. Later that year, he signed with
Eldorado Roma in Italy's
Lega Basket Serie A. In 1980, he moved to play in the Spain's
Liga ACB with the
OAR Ferrol for the 1980–81 season, where he led the league in
scoring and rebounding, while being named Player of the Year. In the 1981–1982 season, he signed with the
FC Barcelona Bàsquet, contributing to the team winning the Spanish league championship. He also competed in the European Cup of Champions. He retired from professional basketball in 1983. ==Career statistics==