[3] On June 24, 2000, DiPietro became the second goaltender in history selected first overall in an NHL Entry Draft when he was chosen by the New York Islanders.
[7][8] DiPietro retired after being released by the Charlotte Checkers of the American Hockey League (AHL) on November 26, 2013, with whom he had signed a tryout contract on October 25.
[10][11] As a result of his contract buyout, the Islanders will continue to pay DiPietro $1.5 million annually until the end of the 2028–29 season.
Islanders general manager Mike Milbury traded incumbent goalie Roberto Luongo to create room for the highly touted DiPietro, who was known for his mobility and puckhandling skills.
[14] DiPietro's NHL debut was widely anticipated, but in 20 games in the 2000–01 season he managed just three wins against 15 losses for a struggling Islanders team.
[16] On March 5, 2007, DiPietro broke an Islanders franchise record by making 56 saves in a 2–1 shootout loss to the New York Rangers.
[19] DiPietro was selected to appear in his first and only All-Star Game in 2008 as a reserve, but was later named the starter after New Jersey Devils goaltender Martin Brodeur dropped out.
He won his first game back and earned an assist, which broke Billy Smith's team record for points by a goaltender.
On January 20, 2009, Islanders general manager Garth Snow announced that DiPietro would miss the rest of the 2008–09 season due to post-arthroscopic surgical swelling in his right knee.
On December 31, the Islanders traded Roloson to the Tampa Bay Lightning, confirming the starting job for DiPietro.
DiPietro returned shortly to finish the season, wearing the old helmet and cage combo worn by former Islanders goaltender Chris Osgood.
During practice for the Islanders' third game, DiPietro took a hard shot to his mask from Brian Rolston, which concussed him and sidelined him indefinitely.
Shortly after, he injured his groin and was again out indefinitely; he later required surgery to repair a hernia in the area, sidelining him for the remainder of the season.
After playing only three games in the lockout shortened 2012–13 season, DiPietro was waived by the Islanders and was sent to their AHL affiliate, the Bridgeport Sound Tigers.
He did not return from the locker room for the second period of play as the game eventually ended 7–3 in favor of the opposing Connecticut Whale.
[7][8] DiPietro signed a professional tryout contract on October 25, 2013, with the Carolina Hurricanes' AHL affiliate, Charlotte Checkers,[24] playing his first game 5 days later in which he stopped 25 of 29 shots in a 5–2 loss to the Grand Rapids Griffins.
[28] He was officially announced as an analyst on National Hockey League (NHL) telecasts on ESPN beginning with the upcoming season on June 29, 2021.
Along with former Islanders teammates Jason Blake and Mark Parrish, DiPietro was named to the United States national hockey team at the 2006 Winter Olympics in Turin, Italy, in February 2006.