In 1989, Helsinki-born Salo competed in the British Formula 3 Championship, racing for Alan Docking Racing. He raced with the Reynard Alfa Romeo package which was not the season's best. Staying with Alan Docking Racing for 1990 and moving to a more competitive Ralt chassis, he raced against countryman and fierce rival Mika Häkkinen in Formula Three, finishing second to him.
In 1991 Salo headed to Japan to race in the Japanese Formula 3000 Championship (now named Super Formula). His initial aim was to race in Europe's Formula 3000 but did not garner enough funding to compete. A budget would have spanned from £200.000 to £500.000 to drive in Europe and Salo had only collected a fraction over £200.000, not enough to stay competitive. While in Japan, Salo landed a competitive seat and got also paid for driving for AD Racing's in their single car team. The Japanese Formula 3000 Championship in 1991 had increased stature thanks to the aggrieved Johnny Herbert (who raced in F1 in 1989) raising the calibre of the championship, driving in Japan in the same time than Salo.
After a few years racing in Japan he made his first Formula One start at the penultimate round of the 1994 season in Japan for the ailing Lotus team. He was kept on for the season's finale in Australia. Following the collapse of Lotus following the end of the season, Salo moved to Tyrrell for 1995. He was to spend three years with the team, scoring points several times. In the 1997 Monaco Grand Prix he completed the whole (rain-shortened and -slowed) race without refuelling, taking fifth place ahead of the faster Giancarlo Fisichella as a result. Despite a promising 1998 with Arrows, he had no full-time drive in 1999.
Following an injury to BAR driver Ricardo Zonta, Salo took his place for three races whilst the Brazilian recovered. However a greater opportunity arose when Michael Schumacher broke his leg in a crash during the 1999 British Grand Prix. Salo was selected as his substitute to partner Eddie Irvine at Ferrari. In his second race in Ferrari at the 1999 German Grand Prix Salo led for part of the race and would have scored a Grand Prix win but team orders demanded that he give the lead to Irvine, who at the time was fighting for the championship with Mika Häkkinen. Following the race, Irvine handed his victory trophy over to Salo as a gesture of gratitude. He also finished third at Monza, ahead of Irvine. These podium finishes were critical in helping Ferrari win their first Constructors' title since 1983.
Salo was back full-time in 2000 with Sauber, taking 11th in the championship, although he left the team at the end of the season to join the new Toyota team in preparation for its Formula One entry in 2002, and also cited a desire to score podiums rather than lower points-scoring positions. He scored two points for Toyota in their first season, becoming the first driver since JJ Lehto at the 1993 South African Grand Prix to score points on a team's debut by finishing sixth at the 2002 Australian Grand Prix. He retired from Formula One at the end of 2002, after surprisingly getting fired from Toyota (though it was later revealed that he was not on good terms with the team due to his deemed poor performance).
During his Formula One career, he achieved two podiums, and scored a total of 33 championship points.
His first post-Formula One race came at the 2003 12 Hours of Sebring, driving the UK-entered Audi R8, the same car he was due to race at the 24 Hours of Le Mans if it had not run out of fuel already after the first hour. He raced in four CART races for PK Racing during the same year, his best finish being third in Miami in his second series start.
Because of his strong links with Ferrari he was picked up to be part of the development program of the Maserati MC12 GT racer. He made his FIA GT debut in 2004, narrowly losing the 24 Hours of Spa-Francorchamps in a Ferrari 575. After that he entered the last four races of the season in the Maserati, winning two races and finishing second once.
2005 was a year somewhat lost in the doldrums with only two participations with the Maserati MC12 in the ALMS GTS-class, a competition where the car turned out to be not even half as competitive as in the FIA GT series.
For 2006, Salo returned to racing full-time, signing with AF Corse in the FIA GT to drive the Ferrari F430 and later on in the year with Risi Competizione in the ALMS. He was victorious in class in the 24 Hours of Spa and finished third in the FIA GT2 Drivers' Championship with 61 points, while his efforts in the ALMS contributed to Risi's Teams' Championship cup. In the following year he continued with Risi Competizione in the ALMS and took the GT2 class honours in the 12 Hours of Sebring and the championship along with teammate Jaime Melo. They won a total of eight races out of twelve in the class. In addition, he won the RAC Tourist Trophy with Thomas Biagi when substituting for Michael Bartels, driving a Maserati MC12 once more.
Salo and Melo with Risi Competizione earned the first team At-Large honours on the 2007 All-American Racing Team, as voted for by the American Auto Racing Writers and Broadcasters (AARWBA). Salo raced again in the ALMS for Risi Competizione in 2008. Although he was not successful in defending his previous year's titles, he won the GT2 class in the 24 Hours of Le Mans, coming in 18th overall.
In 2009, he joined the Risi Ferrari team at the blue-riband races only, the 12 Hours of Sebring, the 24 Hours of Le Mans and the Petit Le Mans event, winning all three of them. Having won these enduro races all more than once, Salo felt he was ready for a new challenge. He set his mind on NASCAR, and had his first test with Michael Waltrip Racing at the half-mile New Smyrna Speedway in November 2009.
From 2010-12, Salo competed in the Gold Coast 600, an endurance event for the V8 Supercars. In 2010, he partnered with Walkinshaw Racing's Andrew Thompson and retired from both races. For 2011-12 he raced with Will Davison and the Ford Performance Racing team, finishing 2nd in the 1st race of 2011 and winning the 2nd race in 2012.
In 2014, driving for Maranello Motorsport, Salo co-drove a Ferrari 458 Italia GT3 to victory at the Bathurst 12 Hour alongside Australian motor racing legends Craig Lowndes and John Bowe, and another local Australian driver Peter Edwards.
He currently resides in Estonia. and has two children with ex-wife Noriko Salo (Endo), son Max and daughter Mai.
His godson Jesse Krohn competes in Formula Renault, both in Scandinavia and the UK.
Like fellow Finns Keke Rosberg and JJ Lehto, both former Formula One drivers, Salo has commentated on several F1 races on MTV3 and the pay-channel MTV3 MAX from 2005 till present (2017).
Since 2011, Salo has been hosting the Finnish TV-show, Virittäjät ('Test Drive by Mika Salo'), along with his former co-host Tomi Tuominen, who is a Finnish journalist, television presenter, sports commentator and former co-driver in the WRC. At first, Salo tests the two cars built by the cars owners, on the Finnish Ahvenisto Race Circuit and present his initial thoughts of the vehicle. He would then proceed to make a quick time attack lap around the track and afterwards give feedback of the car to its owner. At the end of the show, Salo reviews the car with his co-host, Tomi Tuominen. In 2013, the shows format was changed a little for the third season. Now, instead of two cars per episode, Salo drives and reviews only one car, then races the car on the Alastaro Circuit to set a time which the car owner would have to beat. In the last episode of each season, Salo selects a winner out of all the competing cars and shortly explains why he believes that the car and its owner in question deserved to win. The show continues to follow this format to this day and the fifth season of the show was aired on TV, in 2015 and the 6th in 2016.
In 2013, Salo featured in Discovery channel's program called Driven to Extremes along with Hollywood actors Tom Hardy and Adrien Brody. The idea of this TV show was to get behind the wheel to find the driving skills pushed to the limit. Salo joined two episodes, one with Tom Hardy in 50 degrees Celsius in freezing Russia and the other one with Andrian Brody to the exceptionally wet Malaysian jungle at the height of the monsoon season.
Salo's helmet was originally dark blue with a white halo on the top (with a red line inside), 2 white stripes (with a red line inside) going from the rear going down diagonally to the sides of the helmet and a white trapezoidal shape on the chin area (with blue outline), slightly based on Prost's helmet. When he raced in Formula One, he changed the helmet from dark blue to sky blue with the rest of the elements intact.
(key) (Races in bold indicate pole position) (Races in italics indicate fastest lap)
† Cancelled due to California Fires
† Not Eligible for points
(key) (Races in bold indicate pole position) (Races in italics indicate fastest lap)