Sanderson has learned the stoic philosophy and, in the practice, found a way of moving through his life that allows him to appreciate it while it is happening.

The son of retired NHL forward Geoff Sanderson was the first United States-born player to be selected in the 2020 NHL Draft when the Ottawa Senators chose him with the No. 5 pick while also making him the first defenseman taken. He went from No. 11 on the NHL Central Scouting midseason list of North American skaters to No. 4 in the final rankings after excelling for the United States National Team Development Program Under-18 team, where he scored 29 points (seven goals, 22 assists) in 47 games.

Sanderson signed an eight-year, $64.4 million contract with the Senators on Sept. 6, 2023. He had 32 points (four goals, 28 assists) in 77 games last season and was named to the NHL All-Rookie Team in 2022-23.

Sanderson played for the runner-up United States at the 4 Nations Face-Off and won gold with Team USA at the Olympic Winter Games Milano Cortina 2026, the country's first in men's Olympic hockey since the 1980 Lake Placid Games. He was named a finalist for the 2026 Lady Byng Trophy, given annually to the player voted best to combine sportsmanship, gentlemanly conduct and ability as voted on by the Professional Hockey Writers Association, after taking four minor penalties all season.