Larsson made her debut for the Sweden Fed Cup team in 2005, eventually accumulating an overall win–loss record of 50–30.

She was awarded a wildcard for a WTA Tour event in Stockholm, beating Kristina Barrois in three sets, before losing to Swedish No.

She returned to Fed Cup in 2007, losing to Maša Zec Peškirič and beating Vojislava Lukić and Naomi Cavaday, both ranked in the top 300, giving Sweden 9th place.

She ended the season playing Swedish team tennis for Helsingborg alongside Sofia Arvidsson.

She was included in the 2009 Swedish Fed Cup team, along with Sofia Arvidsson, Sandra Roma and Ellen Allgurin.

In Bogotá, she had three wins in qualifying taking her into the main draw where she lost to Carla Suárez Navarro.

In her next tournament in Acapulco, she was forced to retire with a knee injury while trailing top seed Ágnes Szávay one set down.

She started the year playing two $25k events in the United States; in the first tournament in Plantation, she made the final knocking out top seed Maret Ani en route.

She stayed unbeaten in singles and doubles throughout the four ties she played in Fed Cup, Sweden won promotion to the World Group II playoffs.

Larsson made her major main-draw debut at French Open; in the first round she defeated Anastasija Sevastova before losing to Akgul Amanmuradova in the second.

Following Roland Garros, she played the $100k Open de Marseille where she reached the final but lost to Klára Zakopalová.

Larsson then continued her form at the Slovenia Open, as she defeated eighth-seeded Sofia Arvidsson in the first round and Maria Elena Camerin in the second.

Then in the quarterfinals she caused a bigger upset, defeating third seed Anastasia Pavlyuchenkova and Ksenia Pervak to reach her first WTA Tour final.

In the semifinals, she easily beat Sofia Arvidsson to advance to her second WTA Tour final, which she lost to eighth seed Polona Hercog, in straight sets.

Larsson then reached the semifinals of Sony Swedish Open in Båstad, losing to Mathilde Johansson.

[1] In the run up to the US Open, in Cincinnati, Larsson recorded a win over Marion Bartoli (ranked 11 at the time) before losing to Li Na.

Larsson made it to the final of the women's singles at the Swedish Open where she lost to top seed Serena Williams in straight sets, 4–6, 1–6.

In the WTA Challenger event in Ningbo, Larsson made the semifinals, losing to Bojana Jovanovski.