[12] Klara wrote her first song, "Femton mil i min Barbiebil" [Fifteen Scandinavian miles in my Barbie car], when she was six.

[12] This led her to country and folk music stars such as Johnny Cash, Bob Dylan, Leonard Cohen, the Carter Family, Louvin Brothers, Townes Van Zandt, Gram Parsons and Emmylou Harris.

Fascinated by the result, the two began to sing together, first at home and then as street singers in the Stockholm metro and in front of liquor stores.

[10] Klara and Johanna began to write their own country-folk songs inspired by Devendra Banhart and CocoRosie, among others,[12] without much influence from their parents, who were fonder of Patti Smith, Velvet Underground and the Pixies.

[21] It immediately went on air and was listed as one of the best songs of the summer 2007,[22] which led to requests for live performances and even some offers from record companies.

Coincidentally, their younger brother attended the same kindergarten as the daughter of Karin Dreijer, half of Swedish electronic duo The Knife, also known as Fever Ray.

[12] The band subsequently signed with Rabid Records, a label co-owned by The Knife, with conditions that allowed the duo to have full control over their music and album art.

[10] In April 2008, the band released their debut EP Drunken Trees in Sweden, and made their first appearance on Swedish TV.

The duo was relatively well known in Sweden by August 2008, when they uploaded a cover version of "Tiger Mountain Peasant Song" by Fleet Foxes to YouTube.

Robin Pecknold, frontman and lead guitarist for Fleet Foxes, praised the cover on his band's webpage, causing a surge in popularity for the video.

Fleet Foxes performed the day before, and when Pecknold spotted the duo standing at the edge of the stage, they were spontaneously asked to join to sing "Tiger Mountain Peasant Song".

[9]: 34:30–35:10 [19]: 6:15–7:35 Wichita re-released Drunken Trees on 23 February 2009 as an enhanced EP, with "Tiger Mountain Peasant Song" added as a bonus track, along with several videos.

The release was followed by an extensive tour throughout the United States, Canada, Australia, New Zealand and parts of Europe, including Primavera Sound Festival in Barcelona.

[27][28][29][30][31] On 19 November 2009, Klara and Johanna met Conor Oberst after Monsters of Folk's concert in Stockholm, and gave him a demo of their coming album.

[32] Oberst watched the duo perform at the Austin City Limits Music Festival pre-party in Texas on 7 October 2010.

[12] The result was a vinyl single containing cover versions of Buffy Sainte-Marie's "Universal Soldier" and Mel London's and Tampa Red's "It Hurts Me Too".

[41] On 28 August 2012, they performed "America" for the Polar Music Prize winner Paul Simon, who gave the duo a standing ovation.

[42] The song "The Lion's Roar" was featured in episode 2 of series 4 of Misfits,[43] and in the opening sequence of the video game "The Long Dark".

[72][73] The duo sang backing vocals on five songs of Conor Oberst's set at Haldern Pop Festival in Germany on 9 August.

[77] The song was subsequently included on Van William's album Countries, released in January 2018, and peaked at number six on the US AAA chart.

In early 2017, First Aid Kit provided backing vocals for Jesper Lindell's A Little Less Blue EP, which was produced by Sten Booberg and the duo's father, Benkt Söderberg.

[87][88] First Aid Kit held four Leonard Cohen-themed concerts in Spring 2017 with their friends in Dramaten, Stockholm, Sweden.

[98] During Fall 2017, the band gave several interviews in the UK and European media, including the German late night show Inas Nacht (Ina's Night), BBC Radio, Channel 4 TV news and the Channel 4 Sunday Brunch TV programme.

[99] Their performances of "Perfect Places" and "Have Yourself a Merry Little Christmas" were released as "Live From BBC Radio 2" singles in digital format on 18 December 2017.

[130] On 16 October 2019, the duo received the Ulla Billquist scholarship, which is awarded each year to female artists who enrich the Swedish music scene through their artistry.

[131] On 11 December, First Aid Kit played three songs at the Swedish TV's charity program Musikhjälpen with Maja Francis.

[150] On 19 January 2022 First Aid Kit streamed Lion's Roar 10th anniversary concert from Mosebacke Etablissement, Stockholm with brothers Johannes and Gabriel Runemark who will be new band members.

[151] On 8 March 2022 Swedish TV4 aired combined cooking and music program "Benjamin's" episode where Klara and Johanna were guests.

[152] The Swedish version of Come Give Me Love performed with Benjamin Ingrosso in the show was released as a single in various streaming services.

[162] On 7 July 2023 deluxe edition of Palomino album was released with five new tracks added in streaming services and lyric video of Everybody's Got to Learn was published.