Tom Williams had his first major taste of success at the age of 19, when he and his American teammates stunned the hockey world by taking the gold medal at the 1960 Winter Olympics in Squaw Valley, California. During the 1959-60 season, as a member of the U.S. National team, Williams had 21 goals and 17 assists.
After spending a year-and-a-half with the Kingston Frontenacs of the EPHL, Williams joined the Boston Bruins for 26 games during the 1961-62 season, collecting six goals and six assists. His solid play paved the way to a regular roster spot the following year in Beantown, when he had 23 goals and 20 assists in 69 games.
Williams played a total of eight seasons in Boston before moving on to the Minnesota North Stars in 1969-70. His first year in Minnesota resulted in his most productive single-season points total of 67, on 15 goals and 52 assists. He played the better part of another season with the Stars before being sent to the California Golden Seals, considered the worst team in the NHL at the time. Sensing his career was at a stand-still in northern California, Williams opted to jump to the rival WHA for two seasons in an attempt to kick-start his sagging career. He played for two seasons with the New England Whalers, scoring 31 goals and 58 assists in 139 games.
The 1974-75 season saw Williams return to the NHL with the fledgling Washington Capitals. In 73 games he had 22 goals and 36 assists for 58 points. Williams played another 36 games the following season for the struggling Caps, but at the age of 36, knew the end was near. He retired at the conclusion of the 1975-76 NHL season.