Their music is similar to early symphonic progressive rock groups such as Yes, marked by sharp dynamic changes, polyrhythms, heavy bass, vocal harmonies, abstract lyrics, and extended song lengths.

In early 1993, guitarist and singer Roine Stolt had written material for his third solo album The Flower King and sought musicians to perform it.

[2] The five performed their first gig on 20 August 1994 at an outdoor festival in Uppsala, Stolt's hometown and the city where The Flower King was recorded.

Stolt had produced a list of potential titles for the record, one of which was "The Flower King", and chose it because of its positive meaning and its reference to the hippie era of the 1960s.

[2] After performing a series of concerts through 1994, the band entered the studio in December 1994 to record their debut album, Back in the World of Adventures.

In June 2007, they released The Road Back Home, a compilation of remixed songs from 1994 to 2006, plus "Little Deceiver" (a previously unreleased track) and the full version of their cover of "The Cinema Show" by Genesis.

The second box set, titled A Kingdom of Colours 2 and covering the albums Adam and Eve through to Desolation Rose, was released in June 2018.

The band featured Stolt, Fröberg and Reingold with new keyboard player Zach Kamins and new drummer Mirko De Maio.

Roine Stolt stated that he was done being in a group and wanted to tour as a solo artist like Roger Waters or Steven Wilson.

The band toured with Spock's Beard in November and December 2018 and continued to do shows in 2019, this time under the name "The Flower Kings Revisited".

In April 2023, Zach Kamins revealed he left the group due to complicating touring logistics and Daniel Lantz joined for the summer shows.