[2] When he decided to become a professional musician in 1971,[4] he eventually gave up his fulltime job and toured together with Fritz Haberstumpf, Barny Murphy, Willi Augustin and Franz Trojan as "Stummick" at many clubs at American military bases in southern Germany.

In a 2017 interview with Der Spiegel, Sigl was asked about this: Ich dachte: Aha, Bier saufen bis zur Besinnungslosigkeit ist in München in Ordnung — aber käufliche Liebe, das geht nicht.

Mambo had under contract such acts as Sandra,[7] Hubert Kah,[8] Münchener Freiheit[9] and Geier Sturzflug.

[2] As a composer, lyricist and singer, he took part in various musical productions, along with, among others, Nicki in 1985 (he wrote Warum schaust du mi den o and Weil i immer no an Engerl glaub for her, together with Harald Steinhauer and Helmut Frey), Ludwig Seuss in 1991 ("I'm Ready" on the album "Marilyn Sessions"), Hubert Treml in 2006 (in a duet with him with the group b.o.s.s., "Elvis von Schwabing" on the album "Elvis lebt in Untergrammelsdorf")[2] and the hip hop band Blumentopf in 2012.

The music has been described as a "colourful mixture of boogie-woogie – Western swing – blues – rock and roll – ska – chanson and old Schlagers.

[12] Günther Sigl & Band have played at, among other venues, the "Lustspielhaus München",[13] the "Dehnberger Hof Theater",[14] the Stadttheater Landsberg[15] and the "NUTS Kulturfabrik Traunstein".