Liiga Lankinen has played primarily for
HIFK of the
Liiga from 2014 to 2018. He also played one match for
Jokerit and two for
KooKoo, and 10 for
Kiekko-Vantaa of
Mestis. In 2014, Lankinen signed a three-year contract with HIFK. In the 2015 playoffs, he participated in the longest game in Liiga's history, lasting 134 minutes and 14 seconds. His team won 2–1 and advanced to the quarterfinals. In the summer of 2015, Lankinen participated in the
New York Islanders development camp. During the
2015–16 season, Lankinen played alongside
Ville Husso, playing 22 games in the regular season, as well as three in the playoffs as his team won silver medals. During the
2016–17 season, Lankinen was a secondary goaltender alongside the more experienced
Niklas Bäckström, but due to Bäckström's injuries, he became the primary goaltender and played in 42 games, seven of which were shutouts, the most in the league that season. During the
2017–18 season, Lankinen was injured and unable to play for a large portion of the season. However, he made a successful comeback by playing 15 games in the regular season with four shutouts and a save percentage of 94.58 percent. His goals against average (GAA) was 1.33, the lowest in the league that season. During the playoffs, he played as the primary goaltender for 13 games with a save percentage of 93.56 percent, helping his team win bronze medals. He was in the running for the
Urpo Ylönen trophy, which is awarded to the best goaltender of the season, alongside
Veini Vehviläinen from
Oulun Kärpät and
Dominik Hrachovina from
Tappara, but the award went to Vehviläinen.
Chicago Blackhawks On 21 May 2018, Lankinen signed a two-year, entry-level contract with the
Chicago Blackhawks of the
National Hockey League (NHL). In his second season with the Blackhawks'
American Hockey League (AHL) affiliate, the
Rockford IceHogs, in the
2019–20 season, Lankinen made 21 appearances, earning eight wins and represented the IceHogs as the teams' lone representative at the 2020
AHL All-Star Game. On 5 March 2020, Lankinen was ruled out for the remainder of the 2019–20 season after undergoing shoulder surgery, with a recovery period of five months. On 19 January 2021, Lankinen made his NHL debut, losing 5–4 in overtime to the
Florida Panthers. On 22 January, Lankinen earned his first NHL win in a 4–1 win against the
Detroit Red Wings. His first NHL shutout came on 17 February, in the Blackhawks' 2–0 win over the Detroit Red Wings. His
2020—21 season record was 17–14–5. During the
2021—22 season, Lankinen served as the backup to
Marc-André Fleury. Lankinen struggled to begin the season, not recording his first win until 7 November 2021, in a game against the
Nashville Predators. After Fleury was traded to the
Minnesota Wild, Lankinen became the starter, leading the team to a 5–9–3 record following the trade. He ended the season with a 8–15–6 record and a 3.50 goals against average.
Nashville Predators As a free agent from the Blackhawks, on 14 July 2022, Lankinen was signed to a one-year, $1.5 million contract with the Nashville Predators. He was brought in to serve as a backup to
Juuse Saros. On 3 March 2023, the Predators signed Lankinen to a one-year, $2 million contract extension. Across his two seasons in Nashville, Lankinen posted a 20–14–1 record and a .912 save percentage.
Vancouver Canucks On 21 September 2024, Lankinen agreed to a one-year, $875,000 contract with the
Vancouver Canucks. On 1 December, Lankinen recorded a 5–4 overtime win over the Detroit Red Wings, becoming the first goaltender in NHL history to win 10 consecutive road games to begin a season. On 21 February 2025, Lankinen signed a five-year, $22.5 million contract extension with the Canucks. Lankinen has proven exceptionally capable in shootouts, possessing the highest career shootout save percentage in NHL history. ==International play==