The 1999 Stanley Cup playoffs, the championship of the National Hockey League (NHL), began in April, 1999, following the 1998–99 NHL season. The sixteen teams that qualified, eight from each conference, played best-of-7 series for conference quarterfinals, semifinals and championships, and then the conference champions played a best-of-7 series for the Stanley Cup. This is the last time all 4 WHA teams made the playoffs.
The Toronto Maple Leafs and Buffalo Sabres met in the 1999 Eastern Conference Finals. The Maple Leafs were coming off a six-game series win over the Pittsburgh Penguins, while the Sabres were coming off a six-game series win themselves, over the Boston Bruins. Toronto was having its best playoff since 1994, when they last made a conference final series. Buffalo, on the other hand, was in the third round for the second consecutive year.
Dwayne Roloson filled in for injured Sabres goaltender Dominik Hasek, in a close game one at the Air Canada Centre in Toronto. Leading 3–2 midway through the game, Toronto appeared to be in control, but Stu Barnes tied the game for Buffalo at 14:37 of the second period. The Sabres went on to score twice in the third period, on goals by Curtis Brown at 5:21 and Geoff Sanderson at 11:02. Steve Thomas' goal with 6:01 remaining in the game brought Toronto to within one, but Buffalo held on to win 5–4. Roloson impressed the critics, stopping 28 of 32 shots. In game two, the Maple Leafs got two goals 18 seconds apart in the first period, as Steve Sullivan scored at 10:28 followed by Sylvain Cote at 10:46. With just over ten minutes to go in the game, Toronto held a 4–3 lead with Buffalo pressing. Steve Thomas' goal at with 7:43 to go gave the Maple Leafs a 5–3 lead and Garry Valk sealed the 6–3 win with an empty-net goal at 19:30. With series tied at 1–1, the two teams traveled south to the Marine Midland Arena in Buffalo for games three and four. Dominik Hasek returned for the Sabres in game three, but it was the away team that netted the first goal, as Maple Leafs forward Yanic Perreault scored at 16:08 of the first period. But Buffalo was not to be denied, and they scored three goals in the first 7 minutes and 38 seconds of the second period. Alexander Karpovtsev scored at 13:09 of the second to pull the Maple Leafs to within one, but they could not score the equalizer and Curtis Brown iced the game with an empty-net goal at 19:31 of the third period and the Sabres won, 4–2. Dominik Hasek made 24 saves in the victory. Buffalo came out flying again in game four, holding a 5–0 lead after two periods. Hasek's shutout bid was erased when Mats Sundin scored on a penalty shot at 6:59. He scored again with 1:57 remaining in the game as Buffalo won, 5–2. This time Hasek made 31 saves. In game five at the Air Canada Centre on Monday, May 31, the Sabres looked to advance to the Stanley Cup Finals for the first time since 1975. After a scoreless first period, Steve Sullivan got Toronto on the board first just 33 seconds into the second. After goals by Curtis Brown, Kris King and Vaclav Varada, the game was tied 2–2 after two periods. Erik Rasmussen broke the tie with a goal at 11:35 of the third period. With less than two minutes remaining, the Maple Leafs got a power play and pulled Joseph to get a six-on-four situation, could not score on Hasek. Dixon Ward added a shorthanded empty-net net goal with 1:02 remaining as the Sabres went on to win 4–2 and take the series four games to one. With the victory, they advanced to the Stanley Cup Finals for the first time in 24 years.
The Dallas Stars and Colorado Avalanche met in the 1999 Western Conference Finals. Each team had won its previous series in six games, with Dallas ousting the St. Louis Blues and Colorado defeating the Stanley-Cup champion Detroit Red Wings. The Stars were hoping to get back to the Stanley Cup Finals for the first time since 1991, while the Avalanche were trying to get back to the Cup Finals for the second time in four years.
In game one at Reunion Arena in Dallas, the Stars jumped out to a 1–0 lead on Brett Hull's goal at 8:42 of the first period. The Avalanche came back to tie the game in the second period on Peter Forsberg's goal at 14:07. Valeri Kamensky scored the go-ahead goal with 5:58 remaining in the game, as Colorado hung on to win 2–1. Avalanche goaltender Patrick Roy made 30 saves in the victory. With the score tied at 2–2 in game two, Joe Nieuwendyk gave Dallas a 3–2 lead with a goal at 11:52 of the third period. Mike Modano would add a power-play goal with 3:32 remaining as the Stars won 4–2 to tie the series at 1–1. Dallas outshot Colorado 45–19 in the game. In game three at McNichol's Arena in Denver, Ed Belfour stopped all 34 Colorado shots he faced, and Dallas won 3–0. Joe Nieuwendyk, Jamie Langenbrunner and Dave Reid scored for the Stars. The Avalanche came back in game four and led 2–1 with under five minutes remaining in the third period, but Brett Hull scored at 16:07 to tie the score and send the game into overtime. In the extra period, 22 year-old rookie Chris Drury scored at 19:29 to give Colorado a 3–2 win and tie the series at two games apiece. Patrick Roy made 43 saves in the win. Game five in Dallas was the highest-scoring game in the series, as the two teams combined for 12 goals on just 56 shots. Chris Drury and Valeri Kamensky both scored twice as the Avalanche won 7–5. Leading three games to two in the series, Colorado looked to advance to the Stanley Cup Finals at home in game six. The veteran Claude Lemieux got the Avalanche on the board first with just 35 seconds remaining in the first period. However, the Stars responded early in the second on Jere Lehtinen's goal at 1:55. In the third period, Jamie Langenbrunner scored twice at 6:49 at 17:15, and just 14 seconds later, Richard Matvichuk scored to give Dallas a 4–1 lead, which they hung on to. Ed Belfour stopped 26 of 27 Colorado shots. With the series tied at 3–3, the two teams headed back to Reunion Arena for the pivotal game seven. The Stars dominated, building a 4–0 lead in the first 46 minutes and 18 seconds of the game. Mike Keane scored twice and Jamie Langenbrunner and Jere Lehtinen both had goals. Joe Sakic got the Avalanche on the board with a goal with 6:02 remaining in the third, but that was all they would get as Dallas won the game 4–1 and the series four games to three. Ed Belfour needed to make only 18 saves in the victory. With the win, the Stars advanced to the Cup Finals for the first time since 1991 when they were the Minnesota North Stars. Despite getting eliminated, Colorado Avalanche forward Peter Forsberg lead the playoffs in scoring with 24 points in 19 games.
When Brett Hull scored his series-clinching goal in triple overtime of game six, his foot was in the crease but the puck was not. During the middle of the season, the NHL sent out a memo clarifying the "skate in the crease" rule that allowed goals in instances where the goalscorer established possession of the puck prior to entering the crease. On this play, Hull kicked the puck with his left skate (while still outside of the crease) into a shooting position. Because of that action, he became the possessor of the puck prior to his skate entering the crease, which the NHL determined made the goal legitimate. Others have pointed out that similar plays were called differently during the regular season. Many Buffalo fans felt that this call was incorrectly made and the term "No Goal!" became their rallying cry.
Hull's goal ended the series, and the Stars were awarded the Cup. In 1999, it was illegal to score a goal if an offensive player's skate entered the crease before the puck did. At the time, even Dallas Morning News hockey writer Keith Gave questioned the legality of the goal. NHL officials, however, maintained that Hull's two shots in the goal mouth constituted a single possession of the puck since the puck deflected off Hasek, and their ruling stood, citing that they were going to change the rule the following year anyway. Al Strachan, Hockey Writer of the Toronto Sun, and all time NHL scoring leader Wayne Gretzky are on record as saying that the goal was legally scored and should have stood. NHL Director of Officiating Bryan Lewis said there was no crease violation because "Hull had possession of the puck when his skate entered the crease."