Sean Hill was drafted by Montreal in 1988. He continued to play for the University of Wisconsin for the next two years and was part of the 1989 NCAA Championship team. In 1990-91, Hill played for the Badgers and then saw playoff action with Frediericton of the AHL. He made his NHL debut with Montreal during the 1991 playoffs, suiting up for one game with the Canadiens.
The following year was a busy one for Hill, as he skated with the U.S. National Team and the U.S. Olympic Team, as well as playing 42 games in the AHL and four playoff games with Montreal. Hill divided his time during the 1992-93 season between Fredericton and Montreal and had a chance to skate with the Stanley Cup along with his NHL teammates as the Canadiens won the Stanley Cup championships. The Expansion Draft sent Hill to Anaheim where he scored the first goal in Mighty Ducks franchise history.
After a season with the Ducks, Hill was back in Canada playing for the Ottawa Senators. He stayed with the Sens until being traded to Carolina in 1997. It was with the Hurricanes in 1999-00 that Hill recorded career highs in goals (13), assists (31), and total points (44). Hill went on to play parts of three seasons in Carolina before being acquired by the St. Louis Blues in the summer of 2000. With the Blues, Hill battles injuries and was limited to a mere 48 games in his first season with the club. Early into the 2001-02 season, Hill was re-acquired by Carolina and was instrumental in the team's run to the Stalney Cup final against the Detroit Red Wings. After two more season with the Canes, Hill was acquired by the Florida Panthers in the summer of 2004.
As a member of the Panthers, Hill would suit up for 78 games with the club and become a regular in the line-up. His stint with the Panthers however was short lived as he was signed by the New York Islanders in the summer of 2006.
The veteran defenseman laced up in 81 games for the Islanders in 2006-07 and helped the team in its drive for the playoffs. The club would clinch 8th place in the Eastern Conference and qualify for the postseason, however just prior to one of the Islanders playoff games, Hill was suspended by the NHL for testing positive for use of the anabolic steroid boldenone. Hill was unsigned by the Islanders and received a 20-game suspension by the NHL.
On July 6, 2007 Hill was signed as a free agent by the Minnesota Wild.