Early career

Born in Valkeakoski, Kallio started racing in 1997 and won the 1998 Finnish championship in road racing, with further success in the competition in 1999 and 2000. During 2000, he also became the Nordic champion, after finishing second in the prior year.

While Kallio pursued his road racing goals, the Finn has also scored plenty of success in ice racing back home in Finland, having achieved the Finnish motorcycle ice racing championship in 2000, 2004 and 2005 in the 125cc class. At 500cc level, Kallio also won the title in 2004 and 2006.

125cc World Championship (2001–2006)

Kallio made his debut in the 125cc World Championship as a wildcard rider at the 2001 German Grand Prix, but did not finish the race.

Continuing with Ajo Motorsport and the Honda RS125R for a full season in 2002, he finished in the points ten times, nine times in the top-10, with a 5th place in Jerez being the highest of the year. Kallio ended the season with 78 points, 11th in the rider's championship, and won Rookie of the Year, in front of fellow rookies Héctor Barberá, Andrea Dovizioso and Jorge Lorenzo.

He started the 2003 season with Ajo Motorsport, partnering Masao Azuma, but halfway through the season, following him outperforming factory KTM rider Arnaud Vincent, the riders were switched, Kallio being promoted to Red Bull KTM, KTM's factory team. He immediately took his career's best fourth place in Czech Republic, and scored his first ever podium in the 125cc class, a 2nd place at Sepang behind Dani Pedrosa.^[5] Kallio finished the year 11th in the standings, with 88 points.

Kallio racing with his KTM bike.

Signing 2003 Rookie of the Year Casey Stoner to partner 2002 Rookie of the Year Kallio, Red Bull KTM went all in for the 2004 season, but their bikes were full of reliability issues, Stoner being forced to retire five times, and Kallio eight times (including three times from the first six races, and five times from the last seven races of the year). He ended the season 10th in the championship, with 86 points.

The 2005 season would be his breakout year. Stoner moved up to the 250cc category, with Gábor Talmácsi being brought in to be Kallio's new teammate. Kallio started the year well, with a 2nd place in Jerez, before taking his first championship pole position and victory, at the second round of the 2005 season in Estoril. He went on to take another pole in Shanghai but ended the race only in 11th, followed by a 3rd place in Le Mans, another pole with a retirement in Mugello, a pole position and a 3rd place in Barcelona, a fifth consecutive pole position in Assen, followed by a retirement in the race, and a sixth pole in Donnington, where he ended the race in 7th. Following the summer break, he scored his seventh pole position of the year in Germany, his fifth consecutive pole position, both records in the category,^[6] and followed it up with a dominant win, setting fastest lap as well. His pole position streak was halted by main championship rival Thomas Lüthi in Brno, with Lüthi dominating the weekend and winning the race, Kallio coming in second. The two would keep exchanging blows, Kallio winning in Japan and Lüthi in second, Lüthi winning in Malaysia, Kallio finishing in second.

An infamous incident happened in the race in Qatar, with only four races remaining. Kallio started from pole, and led the entire race, closely followed by teammate Gábor Talmácsi. Before the race, Talmácsi had been ordered by the KTM team to stay back and not to fight with Kallio, seeing how he was not a title contender, and would only take away points.^[7] The Hungarian rider stayed behind Kallio the whole race, but in the final lap's finish straight, pulled out from behind Kallio's slipstream and passed the Finn on the last few meters of the race, to take the win by 0.017 seconds.^[8] Talmácsi said that he thought there was one more lap to go, despite the team showing them the board before the final lap, from pitwall. The lost five points turned out to be incredibly valuable to Kallio, as he only finished 5th in Australia, had to retire in Turkey, and went into the final round in Valencia, with a 23-point deficit compared to Lüthi, meaning he needed a win, with the Swiss rider scoring no more than 2 points. Kallio won the final race in Valencia, Lüthi coming home in 9th, meaning Kallio lost the world title by just five points, the exact difference between first place and second place championship points. Both riders had four wins during the season, but Kallio would have had five if not for Qatar, thus winning the title with equal points, but more race wins. Talmácsi was fired after the season finale at Valencia.

Kallio's 125cc KTM bike.

In 2006, Kallio was again a challenger for the 125cc title, and although he produced his career's best season, the young Finn was outshone by Álvaro Bautista, who won the title by 76 points. Kallio was forced to settle for the runner-up spot in the championship again, although he did finish a full 65 points ahead of Héctor Faubel in third position. Kallio scored three victories, in Shanghai, Assen and Motegi, had four pole positions, and finished on the podium 11 times (three victories, seven 2nd places, and a 3rd place) during the 2006 campaign. At the end of the year, viewers of the Finnish motorsport television series Ruutulippu voted Kallio the Finnish Motorsportsman of the Year for the second year running.^[9] He collected 33.1% of all votes and finished in front of enduro world champion Samuli Aro, WRC runner-up Marcus Grönholm and F1 star Kimi Räikkönen.

250cc World Championship (2007–2008)

For the 2007 season, Kallio moved up to KTM's squad in the 250cc category, riding alongside Hiroshi Aoyama. After a difficult start to the season with mechanical woes at Qatar and Spain, Kallio would consistently be fighting around the top six positions, finishing 6th in Turkey, 5th in China, 7th in France, 6th in Catalonia, 6th in Great Britain, and 8th in the Netherlands. The turning point of the season would be at Germany, where Kallio took his debut pole position and podium finish in the class, coming home in 2nd, behind teammate Aoyama, to cap a fine 1–2 for KTM. A 3rd place followed at the Czech Republic, but a nasty highside at San Marino, and more mechanical problems at Portugal cooled off his chances to become Rookie of the Year, and perhaps finish in the top 5. Kallio would capture his first 250cc class victory at the rain-soaked Japanese race,^[10] before crashing out in Australia, a 4th place in Malaysia, and a brilliant win in Valencia, fending off Alex de Angelis on the final lap.^[11] He ended his rookie season with two wins, two pole positions, four podiums and two fastest laps, placing him 7th in the rider standings with 157 points, second among rookies.

Kallio remained at KTM for 2008. A very strong start to the season saw him finish on the podium during the first four races, a 3rd place at the season opener under the floodlights of Qatar, a fortunate win at Jerez after title rivals Álvaro Bautista and Marco Simoncelli crashed out together on the final lap, another solid third place at Portugal, before continuing his strong run with a masterful victory in China under tricky conditions.^[12] Kallio had built up a strong lead in the championship, but his luck would begin to change for the worse with a 5th place in Le Mans, a 4th place in Mugello, and the race in Barcelona, where his bike broke down, causing Kallio to nearly crash on his way back to the pits, resulting in his lead in the championship disappearing. His woes seemed to continue at Donington Park after qualifying only 14th, but he cut through the field fairly quickly, often overtaking multiple riders in a lap, and took a surprise victory. As it later turned out, this was to be his final win in the season, and in the 250cc category, the intermediate class switching to 600cc bikes, and rebranding as Moto2 in the following seasons. The KTM riders struggled to keep up with the pace of Piaggio riders, Kallio finishing 7th in Assen, 4th at the Sachsenring, 5th in Brno, and retiring in Misano. His title challenge was mathematically over in Australia, having been passed by eventual champion Simoncelli and Bautista a few laps before the end of the race, finishing in third place. A technical issue in Malaysia saw him retire on lap 5, and the final round at Valencia ended with Kallio limping home in 11th, having been the only rider to keep pace with the new world champion, Simoncelli, and pushing to the limit to keep up and launch an attack on the final lap, crashing in the overly eager pace. He wrapped up the year to finish 3rd in the overall standings with 196 points, three victories, three 3rd places, and two fastest laps, not scoring a single pole position.

MotoGP World Championship (2009–2010)

On 19 October 2008, Kallio was announced as part of the new Pramac Racing lineup for the 2009 MotoGP season, riding alongside Italian Niccolò Canepa. Kallio was provided with the latest spec Ducati Desmosedici GP9 ensuring equality for the satellite teams and the factory squad.^[13] His MotoGP career started brightly with two 8th places from the opening two rounds at Qatar and Motegi. He then retired from the races in Jerez and Le Mans, before a 13th place in Mugello, and a 9th place in Barcelona. During much of the season however would be blighted with several accidents, most notably at the race in Assen, where Kallio crashed out of 6th place and burnt his finger down to the bone, losing the top section.^[14] He missed the race at Laguna Seca Raceway,^[15] being replaced by Aleix Espargaró, but was back in action at the Sachsenring in Germany, racing with a special custom-made glove to accommodate the bandage.

He finished 14th in Germany, and 10th in England, when prior to the Czech race, Casey Stoner announced that he would miss the next three races due to health problems. Kallio was called in to replace Stoner at the Ducati factory team,^[16] retiring in Brno, finishing 8th in Indinapolis, and 7th in Rimini. Once his stint in place of Stoner was over, Kallio returned to Pramac for the final four races of the season, retiring in Portugal, finishing 9th in Australia, 10th in Malaysia, and 9th in Valencia. Overall it had been a positive debut season in the top class, and his 71 points amassed saw him rewarded with the "Rookie of the Year" award.

Kallio at the 2010 British Grand Prix.

On 30 September 2009, Kallio announced that he had signed a new one-year contract with Pramac Ducati that would see him ride for the team in the 2010 season.^[17] The 2010 season would prove to be an extremely difficult season for Kallio however. His new teammate Aleix Espargaró replaced Canepa, and gave Kallio a harder time than the Italian, often matching or outpacing him. Kallio would only pick up two top-10 finishes throughout the whole season, an impressive 7th at Jerez from the back of the grid, and 9th place at Laguna Seca. On 17 October 2010, Kallio announced that he would not be competing in the final two rounds of the 2010 season, due to a shoulder injury that he had been riding with, since Le Mans in May. Kallio and Pramac parted ways, as he had not been offered a contract for 2011 by the team,^[18] finishing the season with 43 points, 17th in the rider's championship.

Moto2 World Championship (2011–2015)

Return to MotoGP, as test rider (2016–present)

KTM confirmed Kallio as their lead test rider on 27 October 2015, for the upcoming MotoGP project, in preparation for the 2017 season.^[25]

Despite missing out on a full-time race return for the 2017 season, Kallio would at least be rewarded for his testing efforts: a wildcard race entry was granted at the 2016 finale in Valencia, marking his first race back in the premier class since 2010.^[26]

For the 2017 season, Kallio continued testing duties with KTM. The team initially handed the Finn two wildcard entries, at the German and Austrian rounds.^[27] Having narrowly missed out on a points finish at the Sachsenring, Mika produced an impressive display at KTM's home race in Austria, coming through the field to finish as the team's leading rider in 10th place, well ahead of teammate Bradley Smith. Not only was it the team's second top 10 finish of the season, but the result was also the first time a KTM bike had managed to finish a premier class race less than 20 seconds from the race winner.^[28]

After his superb ride in Austria, KTM announced Kallio would be handed his third wildcard of the season at Aragon.^[29] Once more, the Finn produced a strong showing throughout the event. Having automatically qualified through into Q2 in 12th position as the fastest KTM, he would back up his qualifying efforts by coming home in 11th, just behind teammate Espargaro, but some 19 seconds ahead of Smith. After Aragon, the Finn was initially unsure whether he would receive any more race opportunities in 2017, but on 28 September, he was granted a fourth and final wildcard ride at the season finale in Valencia.^[30] Kallio's performances from his wildcard outings put him in contention for a possible full-time ride in place of Smith for 2018. However, on October 11, KTM ended speculation surrounding their rider lineup, electing to keep Smith as the team's race rider for next season, with Kallio continuing his role as KTM's test rider, with plans for more wildcards.^[31]

Kallio suffered a serious knee injury when racing as a scheduled wildcard entry at the Sachsenring, German round in July 2018, disrupting the KTM test programme. KTM was forced to contract Randy De Puniet as a replacement test rider for the remainder of 2018,^[32] and to end any further test-rider entries at races, being too risky for their future plans.^[33][34][35] KTM MotoGP rider Pol Espargaró was also injured soon after.^[32]

In 2019 he replaced Johann Zarco mid-season, after Zarco and KTM broke contract.^[36] Kallio finished the year with seven points in six races.

In November 2020, Kallio was announced to replace Iker Lecuona at the two rounds in Valencia, and the Portuguese GP, after Lecuona tested for positive COVID-19.^[37]

Grand Prix motorcycle racing