Petter Andersson grew up in the village of Ljusvattnet, outside the city of Skellefteå. During his early teens, Andersson competed in cross country skiing and golf as well as playing ice hockey. He was selected to represent the county of Västerbotten in the TV-pucken at age 15, but turned down the offer in order to concentrate on playing football.
He started his football career at the local club Ljusvattnets IF, before moving on to Sunnanå SK where he made his senior debut in Division 5, the seventh highest tier, aged 14. In his later youth years, Andersson played with Skellefteå FF in Division 2, the Swedish fourth tier.
Several top clubs in Allsvenskan soon got interested in securing Andersson's services. Among these where GIF Sundsvall, IFK Göteborg, Malmö FF and Djurgårdens IF, who all failed their attempts. Ultimately, Andersson opted to move to Hammarby IF after several trials with the club. He turned down a move to the fellow Stockholm-based side AIK at a late stage, since the club's luxurious presentation of itself caused a culture crash and scared Andersson off.
After joining Hammarby halfway through the 2003 season, the 18-year-old Andersson made two competitive appearances for his new side the same year. His debut in Allsvenskan came against Örebro SK on October 20 in a 1–1-draw, coming on as a second half-substitute replacing veteran midfielder Christer Fursth, who coincedently played the last game in his professional career.
Ahead of the 2004 season, Hammarby and manager Anders Linderoth promoted several other youngsters to the senior squad on permanent basis; Björn Runström, Fredrik Stoor and Erkan Zengin. Among the newcomers, Andersson made the biggest impact for Hammarby during the same season, establishing himself as a regular. He scored a brace, his first ever goals for Hammarby, on 2 May 2004 in a 2-1 win against Örebro SK on away turf. Weeks later, Andersson scored the lone goal in a 1-0 derby win against fierce rivals AIK on Råsunda. Andersson was mostly used as an offensive central midfielder during the season, as Hammarby finished sixth in the table.
In 2005, Andersson was mainly used as a forward. He scored 6 goals in 25 appearances as Hammarby finished fourth in the league, just missing out on a medal place. Notably, Andersson scored a brace in a 4-0 home win against Landskrona BoIS on 17 July. He also renewed his contract with the club, lasting until the end of 2007.
Half way through the 2006 season, Hammarby was placed first in Allsvenskan. As the new signing Paulinho Guará claimed the striker position, Andersson had returned to the midfield mostly being used as a winger. However, Hammarby dropped of in the table after the summer break and ultimately finished third in the league. Andersson's season was also cut short in July the same year, since he attracted a serious groin injury.
Andersson made his comeback on the pitch on match day 4 of the 2007 Allsvenskan. He scored a brace, both shots being from long range, as Hammarby defeated Brommapojkarna in a 4-0 home win on April 29. Throughout the season, Andersson once again found himself playing as a forward, due to the impressive performances of newly signed Sebastián Eguren on the central midfield. During the summer, Hammarby participated in the UEFA Intertoto Cup 2007. Andersson played a huge part in the campaign, under the reign of new manager Tony Gustavsson, where the club finished as one of the eleven joint winners of the tournament. As a result, Hammarby took part in the 2007–08 UEFA Cup qualification. After knocking out the Norwegian side Fredrikstad in the second qualifying round, Hammarby faced S.C. Braga from Portugal in the next round. On 20 September, Andersson scored a brace as Hammarby won 2-1 on home turf in the first leg. However, Hammarby failed to qualify for the group stage in the tournament as Braga won 6-2 on aggregate. In the domestic league, Hammarby finished in sixth place the same year. Andersson also opted to renew his contract with the club up until the end of 2009.
Petter Andersson retained his excellent form into the 2008 season, now once again playing in his natural role as an offensive midfielder. Notably, Andersson scored a brace in a 4-3 win against IFK Norrköping on home turf in July. Several clubs in other, bigger, European leagues soon got interested in securing the 23-year-old's services. Among these where F.C. Twente, with manager Steve McLaren scouting Andersson in Sweden on several occasions. Hammarby failed to produce any sort of challenge in the league this year and finished on 8th place in the table.
On 1 September 2008, the final day of the international transfer window, he signed for the Dutch club FC Groningen on a 4-year deal. The Eredivisie outfit payed a transfer fee of 880.000 euros, or 8,5 million Swedish crowns, to Hammarby.
Andersson enjoyed a successful start in Groningen while establishing himself as a key player in manager Ron Jans squad, who already consisted of several other Swedish players: Marcus Berg, Andreas Granqvist and Fredrik Stenman. He scored in just his second appearance for Groningen in a game against Heracles, playing as a forward, replacing Stef Nijland that recently had been sold to PSV Eindhoven. In total, he would come to score 4 goals in his first 8 matches for the side. On 25 January 2009 he, however, attracted a serious knee injury in a match against AFC Ajax, which kept him off the pitch for the rest of the season. The club eventually finished sixth in the league.
Ahead of the 2009-10 season, six months later, Andersson returned to training and featured in Groningen's reserve team. He however suffered a major setback as he, once again, tore his cruciate ligament during the fall of 2009. This caused him to miss the whole season.
Andersson made his comeback on the pitch on 23 October 2010, after being sidelined for 22 months because of injuries. He came on as a late substitute in a match against NEC Nijmegen and scored in the 90th minute, deciding the final result to 3-2 in NEC's favour. Andersson would onwards establish himself as a key player in manager Pieter Huistra's starting eleven. Notably, Andersson scored a brace in an important away match against ADO Den Haag, replacing the injured Tim Matavz in the starting eleven. His performance secured a 4–2 win for Groningen on 1 May 2011. Weeks later, on 22 May, Andersson scored again in a match against Heracles in the play-off tournament for one spot in the second qualifying round of the 2011–12 UEFA Europa League. In the end, Groningen however failed to qualify for any international play.
Ahead of the 2011–12 season, Andersson was named the new captain of Groningen, following the departure of fellow Swede Andreas Granqvist to Genoa. Manager Peter Huistra said Andersson was a perfect role model, citing his ability to "handle difficult backlashes" and "good language skills". Injury free, Andersson played a key part as Groningen avoided relegation from the top tier, eventually finishing 14th. He played 33 league games, scoring 4 goals, throughout the whole season. He could, however, not agree terms on a new contract with Groningen. On 18 May 2012, Andersson's departure on a free transfer officially got announced.
In June 2012, Andersson signed a 4-year contract with the Danish club FC Midtjylland. Andersson was brought in to replace Jakob Poulsen on the central midfield, who recently had been signed by Monaco.
He immediately established himself as a key player at Midtjylland. Notably, he scored in a 3-0 win against Randers FC on 12 May 2013 during the later stages of the season. Midtjylland eventually finished sixth in the Danish Superliga and failed to compete for international play. Andersson scored 9 goals, a new career best, in a total of 26 appearances. He attracted interest from the domestic giants FC Copenhagen during the summer of 2013, whilst Midtjylland manager Glen Riddersholm named Andersson as one of the best players in the history of the club.
Andersson eventually remained at the side and continued his fine scoring form into the start of the 2013–14 season. He scored the single goal of the game as Midtjylland won against FC Copenhagen, 1-0, on 28 July 2013. A less severe knee injury would later rule Andersson out from play for almost two months. Andersson would ultimately make 20 league appearances for the side during the season, scoring 6 times, as Midtjylland finished third in the table. Most notably, Andersson scored a brace in a 4-0 away win against AGF Århus on 18 April 2014, with Kristian Bak Nielsen providing the assists for both of the goals. He occasionally also captained the side during the season.
In 2014–15, Midtjylland won the Danish top tier for the first time in the club's history with Andersson being a key player. He featured in 23 league games, scoring 4 goals, as Midtjylland secured the title after a draw against FC Vestsjælland on 21 May 2015.
In the beginning of the 2015–16 season, Midtjylland subsequently took part in the UEFA Europa League qualification rounds. In the play-off round, Midtjylland surprisingly knocked out the English Premier League-side Southampton with 2–1 on aggregate. Andersson played both legs in August 2015 and Claus Steinlein, the club's director of football, named his performances as the best in the team.
Andersson's season would however end soon after, since he was forced to perform surgery on his knees. He managed to appear in four domestic games in the beginning of the season, and played his last minutes of football for Midtjylland on 17 September 2015 against Legia Warsaw in the group stage of the Europa League. Andersson got subbed of at half time, as Midtjylland secured a 1-0 win. On 9 April 2016, Midtjylland confirmed that Andersson was going to leave the club at the expiration of his contract the upcoming summer.
On 16 July 2016, Hammarby IF announced that Petter Andersson had signed a 2.5-year contract with the club. As Andersson still was rehabilitating his injuries, Hammarby's director of football Mats Jingblad told that he would be fully fit in early 2017.
In late 2016, he however chose to retire from football due to major setbacks in his rehabilitation. Petter Andersson did not make a single appearance for Hammarby during this second stint at the Stockholm-based club.
Andersson won 14 caps for the Swedish U17's between 2001-2002, scoring 4 goals. In 2003, he excelled at international level and scored 6 goals in 8 appearances for the Swedish U19's. He also played 20 games for the Swedish U21's between 2004 and 2006.
He debuted for the Swedish national team in 2005.
Andersson's natural position was as an offensive midfielder or second striker. Occasionally, he was also used as a forward or winger.
Among his strengths on the pitch were his play intelligence and powerful shot. He also had a great pace, both with and without the ball at his feet.
Andersson's playing style was sometimes described as irrational and dynamic. Tommy Söderberg, former manager of the Swedish national team, compared him with Fredrik Ljungberg and praised his technique.
He was nicknamed "Ljusvattnets Henry" during his playing career, as a homage to his birth village and the French striker Thierry Henry.As of 5 May 2017.