Sergey Gonchar was the first round pick, 14th overall, of the Washington Capitals in the 1992 NHL Entry Draft. He began his North American career in 1994, suiting up in two playoff games for the Capitals' American Hockey League (AHL) affiliate, the Portland Pirates. He continued with Portland in 1994–95, before making his NHL debut, with the Capitals, on February 7, 1995 against the Buffalo Sabres. He would appear in 31 games total during the lockout-shortened 1994–95 season. The following year, in his first full-length campaign in the NHL, Gonchar would tally 41 points, showing his potential as an effective offensive defenceman. During the 2004–05 NHL lockout, Gonchar returned to Russia to play for Metallurg Magnitogorsk, where he played with future Pittsburgh teammates Petr Sýkora and Evgeni Malkin. During the first game of the 2008–09 pre-season, Sergey was hit into the boards by David Kočí in a game against the Tampa Bay Lightning, dislocating his shoulder. It was reported that he would miss 4–6 months after opting for arthroscopic surgery. Gonchar was sidelined with injuries again for a total of 20 games in the 2009–10 season. Despite missing time, he went on to record his ninth 50-point season in the past 10 seasons, besting Nicklas Lidstrom's eight. He also had his eleventh season with 10 goals or more, tying Sergei Zubov for the most 10+ goal seasons among Russian defencemen.
On July 1, 2010, Gonchar signed a three-year, $16 million contract with the NHL's Ottawa Senators. The deal included a no-trade clause. Gonchar returned to Pittsburgh on October 18, 2010, for a regular season game against the Penguins where he was welcomed by Pittsburgh fans with a standing ovation and highlight reel from his career with the team.