Due to cross-border travel restrictions under the COVID-19 pandemic, the league temporarily realigned this season into four divisions with no conferences. Consequently, a divisional-based playoff format was held, featuring intradivisional matchups in the first two rounds. The four divisional playoff champions were then re-seeded by regular season points in the Stanley Cup Semifinals, with the winners of the Semifinals advancing to the Stanley Cup Finals.
The COVID-19 pandemic impacted the league for the second straight year, with the Government of Canada maintaining its cross-border travel restrictions. Consequently, the league temporarily realigned for this season into four regional divisions with no conferences, putting all seven Canadian teams into one of those divisions. Each team played 56 regular season games, all intra-divisional matchups. The league returned to the traditional 16-team playoff format, with the first two rounds of the playoffs also featuring intra-divisional matchups. This format delayed any possibility of cross-border travel until the third round. The league explored the possibility of having the Canadian team that advanced to the third round hold their home games in a neutral NHL city in the U.S., but were granted a cross-border travel exemption approved by the Public Health Agency of Canada.
Due to local COVID-19 health protocols during the regular season, all 24 American teams hosted a limited amount of in-person spectators while all seven Canadian teams played behind closed doors. During the first three rounds of the playoffs, a number of U.S. teams further increased their capacity, and three of the Canadian playoff teams admitted spectators for the first time, although only the Canadiens offered tickets to the general public. By the time the Finals started, Florida health officials allowed the Lightning to admit 15,000 fans (70 percent of full capacity) at Amalie Arena, but the Canadiens were only limited to 3,500 fans at the Bell Centre after Quebec health officials denied the team's request to increase it to 10,500 (50 percent of capacity).
This was the thirty-fifth Stanley Cup Finals appearance for this team. They have won the Stanley Cup a record twenty-four times (the second most championships in major North American sports behind the New York Yankees' twenty-seven World Series victories). They are the most recent Canadian-based team to win the Stanley Cup, doing so in 1993 (their most recent Finals appearance) against the Los Angeles Kings, winning in five games. They were also the first Canadian-based team since the 2011 Vancouver Canucks to reach the Finals.
On February 24, 2021, head coach Claude Julien was fired after coaching the team through parts of five seasons during his second stint as head coach of the Canadiens, which had registered a 9–5–4 record to start the season. Assistant coach Dominique Ducharme was named interim head coach.
The Lightning took the lead early in the first period. With Tampa Bay forward Erik Cernak joining the rush with Ondrej Palat, Palat passed to an open Cernak who fired a wrist shot past Carey Price resulting in a 1–0 lead for Tampa Bay. In the second period, the Lightning grabbed a 2–0 lead when Blake Coleman's shot through traffic deflected off of Yanni Gourde and into the net. The Canadiens then halved the Lightning's lead as their offensive-zone coverage swept Tampa Bay's end setting up Ben Chiarot for a one-timer and Montreal's first goal of the game. The Lightning regained their two-goal lead in the third period when Nikita Kucherov's shot across the net got swatted by Chiarot and into his own net. After Brayden Point won a faceoff, the puck was picked up by Kucherov who fired a wrist shot past Price to gain a 4–1 lead. Towards the end of the third period and with frustrations boiling over for Montreal, Joel Edmundson took a roughing penalty with 2:40 left in the period. On the ensuing power-play, Kucherov passed to captain Steven Stamkos whose shot got past Price for a 5–1 lead, sealing the victory for the Lightning. The goal ended Montreal's penalty-killing streak at 32.
In game two, the Canadiens poured off more shots than in game one. The first period saw Montreal make thirteen shots compared to Tampa Bay's six. However, neither team was able to score in the opening frame. In the second period, Montreal had more than double the shots of Tampa Bay, yet the Lightning ended up with two goals in contrast to the Canadiens' one. The first Lightning goal came from Anthony Cirelli, whose point shot pinballed in off of Carey Price's blocker and into the net. After Lightning defenceman Mikhail Sergachev commmitted an interference penalty on Artturi Lehkonen, Montreal tied the score on a power-play when Nick Suzuki floated a backhand shot through traffic and under Andrei Vasilevskiy's pads. With 1.1 seconds left in the second period, Tampa Bay forward Barclay Goodrow got past Ben Chiarot forcing a two-on-one with Blake Coleman. Goodrow passed it to Coleman who shot it past Price for the buzzer-beater. In the third period, Montreal continued to pressure the Lightning and Vasilevskiy, however, after a dump-in by Tampa Bay ended up in the Canadiens' zone, an errant pass off the boards by Joel Edmundson gave the puck away to Ondrej Palat, scoring the goal that made it 3–1. At the end of the game, both Corey Perry and Cirelli each received misconducts after an altercation.
In the first four minutes of the first period, the Lightning grabbed a 2–0 lead. The first goal came from a point shot through traffic by Jan Rutta. After Eric Staal shot the puck over the glass causing a power-play for Tampa Bay, Victor Hedman scored the second goal when his point shot bounced off of Carey Price and into the net. The Canadiens were able to score a goal within their seventeen shots as a two-on-one with captain Shea Weber and Phillip Danault allowed the latter's wrist shot to rip off both posts and past Andrei Vasilevskiy. In the second period, the Lightning followed the same momentum from the first period with another two goals in the first four minutes. When an errant change by Montreal created an opening for Ondrej Palat and Nikita Kucherov, Kucherov fired the puck past Price. At 3:33, the Lightning began another two-on-one rush during which Mathieu Joseph's shot rebounded to Tyler Johnson who scored to give Tampa Bay a 4–1 lead. However, just like the first period, Montreal scored which brought their deficit to two. Nick Suzuki, who drove down the right side of Tampa Bay's defensive zone, shot the puck under Vasilevskiy's pads. In the third period, the Lightning mainly held a defensive strategy. In the final five minutes, the Lightning gained a three-goal lead again when defenceman Erik Gustafsson gave the puck away to Johnson and he scored his second goal of the game. The Canadiens quickly rebounded after pulling their goalie and Corey Perry scored top-shelf over Vasilevskiy. However, with the empty net, the Lightning took advantage as Blake Coleman backhanded the puck into the net and the game ended 6–3.
In the first period, the Canadiens scored first, taking their first lead in the series, as Nick Suzuki made a pretty passing play to Josh Anderson who fired it past Andrei Vasilevskiy. The Lightning were able to continue pressuring the Canadiens into the second period. This pressure led to a backhand pass by Ryan McDonagh to Barclay Goodrow as he fired the puck into an open net. In the third period, Alexander Romanov fired a wrist shot from the blue line, scoring to make it 2–1 for Montreal. The Lightning tied it five minutes later when Mathieu Joseph sprung a two-on-one with Patrick Maroon and the latter scored, ending his goal-scoring drought. With the game tied 2–2 after the third period, both teams headed to overtime. In overtime, the Canadiens killed a double-minor penalty caused by Shea Weber and less than a minute later, Anderson put the puck past Vasilevskiy, preventing the first four-game sweep in the Finals since 1998, and winning the game 3–2.
During the first period, Tampa Bay laid an offensive maelstrom on Montreal's goaltender firing thirteen shots compared to the Canadiens' four. Neither team scored in the opening period. The second period held a different storyline as the Canadiens put off ten shots comparably to the Lightning's six shots, yet Tampa Bay scored. Ryan McDonagh provided a secondary assist, setting up David Savard who passed it to Ross Colton tipping in the shot for a 1–0 lead. Tampa Bay then healthily defended their lead throughout the third period, giving Andrei Vasilevskiy the shutout victory and their second consecutive Stanley Cup. Vasilevskiy was awarded the Conn Smythe Trophy as MVP of the playoffs. With their victory, they became the first team since 1983 New York Islanders to win the Stanley Cup without winning an overtime game. Patrick Maroon became the first player to win the Stanley Cup in three consecutive seasons since members of the 1983 New York Islanders accomplished the feat. He also became the first player since Ed Litzenberger in 1963 to win the Stanley Cup in three consecutive years with two different franchises.
In the United States, this was the sixteenth consecutive and final Stanley Cup Finals produced by NBC Sports under their 10-year contract for American television rights to the NHL. NBCSN aired games one and two, while NBC televised the remainder of the series (unlike in the past several years when NBC would have games one and then four through seven, and NBCSN would broadcast games two and three). When the series started, only the first two games was available on Peacock, NBC's streaming service. However, on July 2, the day of game three, NBCUniversal announced that the remainder of the series will also be available on Peacock. Under the new seven-year contracts that will begin next season, coverage of the Stanley Cup Finals will be rotated annually between ABC (who will broadcast their first Stanley Cup Finals since 2004) in even years and TNT (who will broadcast the Stanley Cup Finals for the first time ever in 2023) in odd years.