He first learned how to play the diatonic button accordion from his uncle Ludvik and mastered several songs before he entered primary school.
The turning point in his career came in 1957, when he competed in a radio talent show "Pokaži kaj znaš".
[2] Two years later Slak formed a quartet with his three brothers, playing a trumpet, a clarinet, a bass and the accordion by Lojze.
The group was active for almost 50 years, creating several evergreen songs, including Čez Gorjance (1965), V dolini tihi je vasica mala (1966), Po dekle (1967) and Mama, prihajam domov (1985).
[5] On 20 October 2018, the Museum of Lojze Slak and Tone Pavček opened in Mirna Peč, where, as part of the first phase, a permanent exhibition on Slaka's life and musical journey is on display, with his entire music collection, artefacts and original accordions.