Sidorkiewicz was born on June 29, 1963 in Dąbrowa Białostocka, Poland, but moved to Oshawa, Ontario, Canada, with his family when he was three years old.

[2] Sidorkiewicz joined the Oshawa Generals of the Ontario Hockey League (OHL) in 1980–81,[2] winning three, losing three and no ties (3–3–0) with a 4.68 goals against average (GAA) in seven games.

[5] Sidorkiewicz and fellow netminder and teammate Jeff Hogg won the Dave Pinkney Trophy in the OHL for lowest goals against average.

[2][3] He turned pro in 1984 and was assigned to the Capitals' International Hockey League (IHL) affiliate, the Fort Wayne Komets, sharing the net with Alain Chevrier.

[8] Sidorkiewicz shone with Binghamton and was a leading candidate for the AHL's most valuable player award, helping the team to one of the best records in the league.

[10] Along with Mike Liut and Steve Weeks, Sidorkiewicz was acquired by Hartford's general manager Emile Francis in an effort to rebuild the Whalers.

[3] In the post-season, Sidorkiewicz went 4–4 with a 3.87 GAA in eight games with the AHL Whalers which were eliminated in the Calder Cup semi-finals by the Baltimore Skipjacks.

On October 15, 1988, Sidorkiewicz earned his first career NHL victory, defeating the Chicago Blackhawks 7–5 at the Hartford Civic Center, saving 25 of the 30 shots he faced and teammate Ron Francis picked up two goals.

[3] In two playoff games, Sidorkiewicz went 0–2 with a 3.87 GAA and a .822 save percentage[3] as the club was swept by the Montreal Canadiens in the Adams Division semi-finals, splitting time with Kay Whitmore.

[23][24] Sidorkiewicz finished fourth in Calder Memorial Trophy voting[25] and was named to the NHL All-Rookie Team.

[3] In six playoff games, he had a 2–4 record with a 4.01 GAA and .862 save percentage[3] as Hartford lost to the Boston Bruins for the second straight season.

[3] With Whitmore and Sidorkiewicz struggling, general manager Ed Johnston acquired goalie Frank Pietrangelo from the Pittsburgh Penguins at the trade deadline on March 11, 1992.

[3] Sidorkiewicz, despite his statistics, became a fan favourite in Ottawa and appeared in the 44th National Hockey League All-Star Game held at the Montreal Forum.

[36] After just one season, on June 20, 1993, the Senators traded Sidorkiewicz and future considerations to the New Jersey Devils for Craig Billington and Troy Mallette and a fourth-round draft choice.

[3] The shoulder injury that kept him out of the lineup allowed for the emergence of Martin Brodeur in New Jersey's net alongside Chris Terreri.

Sidorkiewicz spent the remainder of the season splitting time between the Albany River Rats of the AHL and the Fort Wayne Komets of the IHL.

[3] Sidorkiewicz became the River Rats starting goaltender in 1996–97, earning a 31–23–6 record in 62 games, while posting a 2.90 GAA and a .901 save percentage.

[3] Sidorkiewicz made his final NHL appearance in the 1997–98 season on December 30, 1997, playing the third period allowing one goal, in a 6–2 loss to the Chicago Blackhawks.

[47] In his first and only full season as the Otters head coach, Sidorkiewicz led the rebuilding club to a 15–50–3 record, failing to qualify for the playoffs.