After two seasons in the OHL with the Sault Ste. Marie Greyhounds, Steve Sullivan was selected by the New Jersey Devils in the 1994 NHL Entry Draft. He made his NHL debut in the 1995-96 season while spending the majority of his first two seasons with the team's AHL affiliate in Albany where he was named to the league's first all-star team and captured a Calder Cup title in 1995. The next year saw him split the season once again as well as being traded to the Toronto Maple Leafs.
Sullivan spent the next three seasons in Toronto before being claimed off waivers by the Chicago Blackhawks, where he blossomed into a bona fide point-producer. The 2000-01 season was Sullivan's most productive in the NHL as he led the Blackhawks in scoring, as well as the league in short-handed goals and points.
Although small in stature, Sullivan is a crafty player with breakaway speed who after dominating the AHL in the mid 1990s, took his game to the NHL and once the 2002-03 season came to an end had scored five straight 20-plus goal seasons and five straight 40-plus point seasons. In February 2004, after parts of five seasons in the Windy City, Sullivan was dealt to the Nashville Predators who were looking for an offensive threat. Upon his arrival with the Preds, Sullivan to register 30 points (9-21-30) in 24 games, while leading the club to its first playoff appearance in franchise history.
On the international stage Sullivan made his debut at the 2000 World Championships and returned again the following year.
In 2009, Sullivan would become the first player in Nashville Predators franchise history to capture a major NHL award, winning the Masterton Trophy for his dedication and perseverance in returning from a serious back injury after being away from the game for a total of 687 days. After sustaining the injury on February 22, 2007, Sullivan would miss 142 regular season games and 11 more in the playoffs, finally making his return to action on January 10, 2009 versus Chicago. He would record his first point the very next game and after a slow start, finished the year by notching 27 points in the Predators' final 25 games, leading the club to a 22-14-5 record down the stretch. An inspiration to both his teammates and the community for his hard work and training that enabled him to return to the NHL; Sullivan also recorded his milestone 600th career point on March 28 versus Los Angeles.
During the 2010-11 season, injuries once again took their toll on Sullivan. He was limited to just 44 games due to sports hernia surgery, but did manage to put up 22 points.
In the summer of 2011 Sullivan and the Predators would part ways. As an unrestricted free agent he signed with the Pittsburgh Penguins on July 1.
In his one season in Pittsburgh, Sullivan would record 17 goals and 31 assists. He would find himself a free agent again the following summer and signed on to join the Phoenix Coyotes.
Sullivan appeared in 33 games for the Coyotes during the lockout shortened 2012-13 season, but struggled to find his scoring touch. On April 3, 2013, the NHL trade deadline he was sent to the New Jersey Devils in exchange for a draft pick.