Raven and Larsen come from Lørenskog in the district east of Oslo. They had known each other since the age of five. Discovered by the Norwegian music producers Kenneth M. Lewis and Kai Robøle, the girls were signed to Atlantic Records in 1998. The name "M2M" was chosen from a contest held for fans to give a name to the band, having been previously known as Marion & Marit. The group's first single, "Don't Say You Love Me", appeared in 1999, and was featured on the soundtrack of Pokémon: The First Movie (albeit with a small edit to the lyrics). The film helped the song to reach success worldwide, including peaking at No. 16 in the UK Singles Chart, their only hit in the UK. The duo released their first album Shades of Purple in 2000. It debuted at number one in Norway and several Asian countries, entering the Top 40 for most other countries. In September that year, they toured with Hanson, performing as the boys' opening act. Earlier in the year, they performed a concert special at Epcot in Walt Disney World, broadcast on April 29, 2000, under the name "M2M and BBMak in Concert", performing six songs with breaks in between of them walking around the park.
Four more singles were released from the album: "Mirror Mirror", "The Day You Went Away", "Pretty Boy" and "Everything You Do". They enjoyed some popularity in Asia; releasing a song sung in Mandarin, "Pretty Boy". However they did not record a Mandarin version of their hit "The Day You Went Away", and Taiwanese singer Cyndi Wang recorded her own version.
In 2002, the duo returned with a more mature, less pop-oriented sound with their second album, The Big Room. In two years, their voices had changed, particularly Raven's. The first single from the album was "Everything" followed by "What You Do About Me". They did not release a third single, even though "Don't" was released to U.S. and Latin America's radio stations and "Wanna Be Where You Are" was released in the Philippines. The promotion for their second record included TV appearances that year, including a spot on the WB's Dawson's Creek, appearing in the 100th episode of the show towards the end of its fifth year. That year, they also took part in the Pantene Pro-Voice concert series that aired on the now defunct MuchMusic USA. While on tour with Jewel, M2M was dropped by Atlantic Records, who cited a lack of record sales, although the album did do well in Norway, Asia and Australia.