Sampson's hockey career began at Boston College in the ECAC. Gary played four years of collegiate hockey at BC from 1978 to 1982. He scored 31 goals and 94 points in 106 games before joining the United States National Team for the 1982-83 season. He also played for the National Team in 1983-84 and was a member of Team USA at the 1984 Winter Olympics. The Olympics were the highlite of Gary's career.
“It was really special because my father played in the Olympics, too, in the ’56 Olympics. And when you come from a town like mine, which was only 6,000 people, it was special. So I was excited to make it because I had no plans of making it. So it was kind of a big surprise. I guess playing for your country was memorable especially with all the recognition we had because it was right after the 1980 Games and they had high expectations of us hopefully maybe winning another gold. So the coverage we had was just unbelievable. And we played in several countries over in Europe. Everywhere we went, we were big celebrities. It didn’t matter who you were. But again, coming from a small town, it was just unbelievable. Most of the time I didn’t get to travel. So playing in Tokyo and Finland and Holland and Switzerland, those memories, you just can’t forget them.”
Following the Olympics, Sampson signed as a free agent with the Washington Capitals. Gary finished the season playing in 15 games with the Capitals to close out the 1983-84 campaign. He scored his first NHL goal in Minnesota which was extra special for Gary.
"Of course you always remember your first goal which was against Minnesota, my hometown. So that was something I’ll never forget.”
Gary added his second career goal in the 1984 playoffs.
Gary played in a career high 46 games with Washington in 1984-85, recording 10 goals, 15 assists and 25 points, all career bests.
Sampson split the following two seasons between the Capitals and their AHL affiliate in Binghamton before playing his final year of professional hockey in 1987-88 with the Baltimore Skipjacks of the American Hockey League.
Upon hanging up the blades, Sampson’s career NHL statistics included 13 goals, 22 assists and 35 points in 105 regular season games.
Following his playing career, Sampson entered the coaching ranks before opening up a very successful fishing lodge in Alaska.