Born and raised in Espoo, Lappalainen started his karting career in 2012. His best result was winning the Finnish Karting Championship in the OK class in 2016.
Lower formulae
In 2016 Lappalainen made his single-seater racing debut with part-time appearances in the F4 Spanish Championship. He finished all races in the top ten, however due to him being a guest driver Lappalainen didn't score any points.[3]
The next year the Finn continued racing in Spain, whilst also driving in SMP F4. He struggled in both series however, finishing 15th and 13th in the respective championships.
In 2018, Lappalainen continued in the SMP F4 Championship. He won seven races and scored 15 podiums, winning the championship 41 points ahead of Michael Belov.[4]
Formula Regional European Championship
In 2019 KIC Motorsport announced that Lappalainen would drive for them in the inaugural season of the Formula Regional European Championship alongside Isac Blomqvist.[5] He finished third at the Red Bull Ring, the only podium of his season, and ended the season in 11th in the standings.
Lappalainen would continue driving for KIC in 2020.[6] His season would be much more successful, with the Finn scoring two podiums and finishing sixth in the drivers' championship, although Lappalainen was beaten by his teammate Patrik Pasma.
Sportscar career
In 2021, Lappalainen would move across to sportscar racing, driving for Emil Frey Racing in both the GT World Challenge Europe Endurance and Sprint cups.[7] Partnering Jack Aitken and Arthur Rougier in the former, the trio would fail to score in the opening three rounds; this negative streak being compounded by a crash which injured Aitken at the 24 Hours of Spa.[8] At the final two races however, the team were able to take a pair of top-six finishes, leading Lappalainen to finish 16th in the standings.
The following year, a return to Emil Frey in the Silver Cup class of the GTWC Europe Endurance Cup was coupled with a full-time campaign in the ADAC GT Masters, in which Lappalainen would be joined by Mick Wishofer.[9][10] Lappalainen's campaign in GT Masters yielded little success, as he and Wishofer ended up 17th overall, though the pair managed to take victory at Zandvoort, where a pole position and charging first stint by Wishofer gave Lappalainen to take over the car in first position, leading to an uninterrupted run towards the checkered flag.[11] In the Endurance Cup, Lappalainen managed to finish on the podium of his class at the 24 Hours of Spa, before taking the team's only class win at the Hockenheimring.[12][13] Another podium at the season finale in Barcelona earned the team third place in the Silver Cup championship.[14]
Remaining with Emil Frey for a third successive season in 2023, the Finnish driver would concentrate his efforts to compete in the GT World Challenge Europe Sprint Cup alongside Giacomo Altoè, driving the new Ferrari 296 GT3.[2] After two points-earning races at Brands Hatch to start the season off, Lappalainen and Altoè would score their first podium of the year in Misano, finishing second.[15] After a pointless round in Germany the pair went on to finish inside the top ten in all remaining races, thus ending up seventh in the standings. Lappalainen went into the 2024 season with Emil Frey once more, this time together with Ben Green.[16]