With his fellow comedian Timo Kahilainen he owned Porkkana Ryhmä Oy ("Carrot Group Inc."), which produces Kummeli's output.

It includes Silvennoinen's own song "Sun Don't You Shine" and a cover of "Fire" by Jimi Hendrix.

Of the four-member group, Silvennoinen had the largest number of different roles (including reporter Mauno Ahonen, summer cottage neighbour Martti Mielikäinen, Matti Näsä who complains about everything, and officer Jaakko Parantainen who is concerned about environmental questions).

The most lucrative song – from the point of view of royalties – Silvennoinen ever wrote was "Jumankauta juu nääs päivää" that he claims to have done in 20 minutes.

It features the Kummeli character Matti Näsä singing about his car, a Toyota Mark II.

In 2005 guitarist Jukka Tolonen and singer Mikko Kuustonen joined the group in order to make their second album, Joutomailla.

In the 2000s Silvennoinen did voice acting work for some children movie characters needing Finnish overdubs.

Silvennoinen passed away in his sleep after a long illness at his home in Pälkäne, Finland in the morning of the 18th of December 2024.