Since winning Melodi Grand Prix Junior in 2012, they have won numerous prizes, such as Spellemannprisen in 2017.

[4][5] In 2012, Marcus and Martinus were contestants on the eleventh season of Melodi Grand Prix Junior.

The first, "Girls", featuring Madcon, debuted at number 1 in Norway[12] and became their second single to reach the top 100 in Sweden after "Elektrisk".

The second and third, "Heartbeat" and "I Don't Wanna Fall in Love", followed just days after the release of "Girls" and debuted at numbers 21 and 37, respectively.

As the Young Talent Act of the 2016 Nobel Peace Prize Concert, they performed "Without You" and "Bae" at Telenor Arena in Norway on 11 December 2016.

On the 13 May, Marcus and Martinus announced the Jury points for Norway in the Eurovision Song Contest 2017.

[16] The same month, on 14 July, they performed on Swedish Crown Princess Victoria's 40th birthday with their own song, "On This Day", written especially for her.

[23] In 2023, they entered Melodifestivalen 2023 with the song "Air",[24] ultimately finishing in second place behind Loreen's "Tattoo".

[25] "Air" went on to win the OGAE Second Chance Contest for 2023 giving Sweden its 19th victory overall with Norway and Finland rounding out the top three.

[26][27] On 9 March, the duo won Melodifestivalen with 177 points, and represented host nation Sweden in the Eurovision Song Contest 2024 in Malmö.

[30] After Eurovision, they released the album Unforgettable on May 31, 2024, which contained the singles they've been publishing the past few years, including a couple of new songs.