In spring 1966 Walli launched his professional musical career as guitarist when he started playing with Jormas, a band which was extremely popular not only in Finland but in the rest of Scandinavia too.

Following the split of Blues Section, Hasse Walli played for some time in the band of light pop singer Tapani Kansa and as a bar musician at the restaurant Fennia.

Walli's injured left hand was operated and the guitarist, forced to take a break from playing, spent some time in the bohemian circles of Copenhagen, leading a vagrant life also as a street musician in French Riviera.

After returning to Finland, Hasse Walli played for a while with Kirka & D'Islanders, in a band called Zeus producing Vesa-Matti Loiri's first album 4+20 and collaborating with jazz musician Make Lievonen.

Hasse Walli Eternal Band was a jazzy project which worked under different line-ups from 1968 to 1971, playing among all at the first Ruisrock festival of Turku in 1970.

The best known Piirpauke track is the hypnotic Konevitsan kirkonkellot from the band's eponymous 1975 debut album, based on a traditional Karelian folk song.

By this time Walli had seriously gotten into African music, and he dissolved the band and travelled in January 1982 to Dakar, the capital of Senegal, to explore local sounds such as Mbalax, Senegalese pop.

Jamming with local musicians at clubs, Walli practiced hard to get into the heart of this musical style quite differing from the Western genres of rock, blues and jazz he had already learned to master.

Afro-Line was another band of Walli he started with Congolese expatriate Marie-Alphonse Liwata, releasing the albums Viva Africa (1983), Dakar Nights (1985) and Close to the Line (1987).

Soon got together the new band, called Asamaan, with such musicians as Manel Diop, Yamar Thiam, Aladji Oumar Faye, Omar Cheikh Diene, Pape Sarr and Mousse Gueye.

Hasse Walli also played several Back to the 60s type of concerts with some his peers from that period such as Danny; never forgetting his love of African music, either.