Tokarski played midget for the Prince Albert Mintos and led the team to capture the Telus Cup, Canada's midget hockey championship in 2006. Tokarski had three shutouts and a 1.98 goals against average for the Mintos. He was added to the protected list of the Western Hockey League 's Spokane Chiefs in December. He played a combined 30 games in his first season with Spokane, posting a record of 13 wins, 11 losses and 2 overtime losses. Tokarski then took over as the Chiefs' starting goaltender in 2007–08. He played every game for the Chiefs in the playoffs, leading them to the Ed Chynoweth Cup by conceding just 31 goals in 21 playoff games. The Chiefs' title earned them a berth in the 2008Memorial Cup, Canada's national junior championship. With Tokarski in net, Spokane won all three games in the round robin to earn a berth in the championship game. Tokarski made 53 saves in the final as Spokane defeated the Ontario Hockey League 's Kitchener Rangers to claim the Chiefs' second Memorial Cup championship in franchise history. His performance earned him the Hap Emms Memorial Trophy as the tournament's outstanding goaltender, and the Stafford Smythe Memorial Trophy as the most valuable player. Tokarski was selected by the Tampa Bay Lightning in the fifth round of the 2008 NHL Entry Draft.
Professional
Tampa Bay Lightning
Tokarski made the transition to professional hockey during the 2009–10 season, primarily playing for the Lightning's American Hockey League affiliate, the Norfolk Admirals. In 55 games for the Admirals, Tokarski amassed a 27–25–3 record. He made his NHL debut on January 19, 2010, against the New York Rangers, replacing Antero Niittymäki in the third period after the latter had surrendered six goals. Tokarski made his first NHL start on March 8, 2012, against the Washington Capitals. He had 29 saves on 32 shots and let three pucks by for a 3–2 Lightning overtime loss. He and the Admirals would eventually go on to win the Calder Cup as AHL champions.
On February 14, 2013, Tokarski was traded to the Montreal Canadiens in exchange for goaltender Cédrick Desjardins. On March 5, 2014, Tokarski played his first game with Montreal, a 4–3 shootout victory over the Anaheim Ducks. On March 16, he recorded his first NHL shutout in a 2–0 win over the Buffalo Sabres, stopping all 29 of Buffalo's shots. On 19 May, it was announced Tokarski would be starting in place of Montreal's Carey Price due to a suspected sprained knee Price sustained against the New York Rangers. He started Game 2 of the Eastern Conference Finals against the Rangers but stumbled in his first playoff game with a 3–1 loss. He remained solid in the third period but the Canadiens had problems getting goal scoring. In Game 3, Tokarski made 35 saves on 37 shots to help the Canadiens win 3–2 in overtime, cutting the Rangers' series lead to 2–1. In Game 4, he played well and had a good chance to have a win but lost in overtime, 3–2. In Game 5, he then led the team to a 7–4 win, staving off elimination and reducing the Rangers' lead to 3–2 in the series. In Game 6, he stopped 31 shots on 32 shots to give his team a chance to win. Although the Canadiens lost the series 4–2 against New York, Tokarski's performance earned high praises. Following the conclusion of the Canadiens' 2014–15 pre-season, goaltender Peter Budaj was traded to the Winnipeg Jets on October 6, 2014, effectively leaving Tokarski as Carey Price's backup for the regular season. At the beginning of the 2015–16 season, on October 5, 2015, Tokarski was placed on waivers, ending his tenure as backup goaltender for the NHL club. After fellow Canadiens' prospect Mike Condon had a strong showing in training camp, the team took him over Tokarski. with the Checkers in 2019.
Anaheim Ducks
On January 7, 2016, Tokarski was traded to the Anaheim Ducks in exchange for Max Friberg. His lone appearance for the Ducks came on October 28, 2016, where he stopped all five shots faced in relief during a 4–0 loss to the Columbus Blue Jackets. Tokarski went for the Ducks' AHL affiliate, the San Diego Gulls.
On October 9, 2017, Tokarski was traded to the Philadelphia Flyers in exchange for future considerations.
New York Rangers
On August 20, 2018, as a free agent, Tokarski signed a one-year, two-way contract with the New York Rangers. He was assigned to the Rangers AHL affiliate, the Hartford Wolf Pack, to begin the 2018–19 season. Tokarski was rotated through starts during the season with the Wolf Pack, and made 21 appearances for 10 wins. He was recalled to the Rangers' roster on two occasions however did not play. On February 28, 2019, Tokarski was re-assigned by the Rangers to the Charlotte Checkers of the AHL. In a related move the Checkers NHL affiliate, the Carolina Hurricanes re-assigned prospect Josh Wesley from the Checkers to the Wolf Pack. In joining the Checkers, adding a veteran presence as the team's backup, Tokarski went undefeated in 7 regular season games and 5 playoff contests to help the Checker claim the Calder Cup, his second AHL championship.
Wilkes-Barre/Scranton Penguins
On July 8, 2019, Tokarski signed a one-year contract with the Wilkes-Barre/Scranton Penguins. He followed Mike Vellucci, who was his head coach with the Checkers.
International play
Tokarski was named to Canada's roster for the 2009 World Junior Ice Hockey Championships. He struggled during the tournament, entering the final as the eighth-best tournament goaltender statistically, though he led Canada to thrilling 7–4 and 6–5 wins over the United States and Russia, respectively. Tokarski played his best game in the final, posting 39 saves on 40 shots as Canada defeated Sweden 5–1 to win its fifth consecutive gold medal.
