Merzļikins played his junior hockey in Switzerland with HC Lugano, which allowed him to play in the NL with a Swiss player license and not count as an import player. Throughout the 2012–13 season, Merzļikins spent several games on the bench as the backup goaltender of HC Lugano. Merzļikins would eventually make his NL debut on 28 September 2013 in a 2–1 victory over Lausanne HC. At the end of the 2013–14 season, Merzļikins was voted off as NL Media Most Improved Player and NL Youngster of the Year. Touted by the scouting services, Merzļikins as a result was selected in the third round, 76th overall, of the 2014 NHL Entry Draft by the Columbus Blue Jackets. In the 2015–16 season, Merzļikins enjoyed a breakout year after leading the league in saves and ranking second in SV% and fifth in wins with a 23–13–4 record in 44 contests. In the 2016 NLA playoffs, Merzļikins led Lugano to the NL final which they would eventually lose in 5 games to SC Bern. He posted a.937 save % and 2.32 goal average in 15 playoffs games. His standout season was acknowledged by claiming the Jacques Plante Trophy as the League's best goalie. On 22 June 2016, he agreed to a three-year contract extension with Lugano, without an NHL out-clause. At the 2016 Spengler Cup, he was named to the tournament's all-star team. In the 2017–18 season, Merzļikins captured his second Jacques Plante Trophy as the league's Goaltender of the Year after finishing fourth in wins and fifth in saver percentage with a 19–15–1 record in 40 contests. Merzļikins returned for his sixth and last season under contract with HC Lugano in the 2018–19 campaign. He posted a 22–18–0 record with a 2.44 goals against average,.921 save percentage and a career-high five shutouts in 43 games. He was unable to prevent Lugano being swept in the first-round of the playoffs against EV Zug.
NHL
At the conclusion of the season with Lugano, Merzļikins left Switzerland and agreed to immediately join the Columbus Blue Jackets for the remainder of their season, signing a one-year, entry-level contract, on 20 March 2019. His NHL debut came on 5 October 2019 against the Pittsburgh Penguins. Merzļikins allowed seven goals in the game, earning the loss. He was sent down to the Cleveland Monsters of the AHL on 6 November, later making one appearance with the Monsters before returning to the Blue Jackets. Towards the end of 2019, Merzļikins was not getting many starts, as he had yet to win a game in the NHL. Due to an injury to Joonas Korpisalo on 30 December, Merzļikins started the 31 December game and earned his first NHL win against the Florida Panthers, where he allowed one goal on 37 shots and helped Columbus to a 4–1 victory. On 11 January 2020, Merzļikins recorded his first career NHL shutout in a 3–0 win over the Vegas Golden Knights. In 23 April 2020, the Blue Jackets signed Merzļikins to a two-year contract extension.
Merzļikins was born in Riga, Latvia. Merzlikins was named after Elvis Presley, of whom his father was a fan. Merzlikins speaks Latvian, English, Russian and Italian.
