His first three seasons were spent mainly with the Pittsburgh Hornets of the AHL before playing in Detroit in 1966-67 and half of 1967-68 before a trade sent him to the Oakland Seals, where he would be named the second ever recipient of the Bill Masterton Trophy at the conclusion of the season for perseverance, sportsmanship and dedication to hockey.
Hampson would play three more seasons with Oakland, including setting an NHL career best with 26 goals and 75 points and appearing in the NHL All-Star Game in during the 1968-69 season before being dealt late in the 1970-71 season to the Minnesota North Stars. After playing the 1971-72 season with the North Stars, Hampson would move across the river to St. Paul to join the brand new Fighting Saints of the WHA for the league's debut season of 1972-73, where Hampson would be named the team's captain due to his veteran leadership and win the WHA's first "Most Gentlemanly Player" Award.
After three and a half seasons the Fighting Saints would fold due to financial difficulties. Hampson them finished out the 1975-76 season with the Quebec Nordiques. After sitting out two seasons, he would return to the ice in 1978-79 with the Oklahoma City Stars of the CHL for 23 games and make token appearances of 3 and 6 games in 1979-80 and 1980-81 before his playing days were completed for good.