KSMB never fared very well with the critics. But while they've always stood in the shadows of the critically hailed Ebba Grön, at their height of fame in the early '80s they were able to draw almost as big crowds. Where Ebba Grön were angry and serious and in some ways lyrical, KSMB were more playful and had a stronger "don't give a damn" attitude. Maybe KSMB didn't have the same talent when it came to lyrics, but this, together with their approach and their singalong friendliness, in a way only made them more punk. After their first album, KSMB developed a slightly softer sound, similar to what would later be called punk-pop. The band only held together until 1982, but the last year it was one of the most popular live acts in Sweden.
When the 14-man school band Skärholmens Gymnasiums Punk-Ensemble broke up after their first and only concert, the remnants formed into KSMB. In spring 1978 they had their first gigs at small clubs around Stockholm and started a PR campaign consisting in tagging their name all over town. Their first big concert was at a festival that summer, but just before the gig both guitarists quit, which meant drummer Johansson had to play guitar and the band had to find a new drummer. A number of musicians came and went, until in 1979 a more steady setting had formed, with Johansson on drums, Sylvan on guitar, Nilsson on bass, and two vocalists: Guiance and Alonzo. A number of concerts at youth centers followed. At one the band was contacted by representatives from MNW, who wanted to record them for an album with young alternative bands. The result was Bakverk 80 and the other bands participating were Incest Brothers and Travolta Kids.
This album sent KSMB out on their first nationwide tour, and in spring 1980, their debut album Aktion was released. After finishing the recording, Sylvan left the band and was replaced by Sjölander. Stefan Sundström, who was later to become known as a singer/songwriter, was also tried out as second guitarist. While declining, he recommended his friend Jonson, also known as Guld-Lars. Soon bassist Nilsson too left the band, and with temporary bassists, KSMB started a period with intensive touring, playing prisons as well as rock clubs, but to very little pay. With Ulvesjö on bass, Rika Barn Leka Bäst was released in 1981. It is widely regarded as the worst of KSMB's only three albums and was also a step away from pure punk. One track, for example, included a brass ensemble. Now Alonzo left the band, which set out on a new tour that was even more intensive than the previous one. First touring Sweden, they later teamed up with Before and Kjött for the rest of Scandinavia. But even this brought very little money to the band, actually hardly enough to pay the rent for the equipment. A new album was planned for 1982, but there had been no time to write new material. Johansson, who wrote most of the songs, demanded a one-month break to come up with a new repertoire. The rest of the band refused, since they didn't have any money and no jobs to go back to. A single was recorded in 1982 but was not released. In March Johansson and Jonson quit. The remaining band soon fell together, but they all reunited a month later for two concerts. Johansson convinced Alonzo to join the band for a last time, and one of the concerts was recorded and released as Dé É För Mycke in October the same year.
After this it was finally over. Johansson formed Strindbergs and would later start a career as singer/songwriter and producer, Alonzo sang in Stockholms Negrer and the other members went to more or less obscure bands. In 1993, KSMB reunited, this time without Johansson. They wrote a number of new songs, but lacking Johansson as songwriter, they weren't very successful.