Atos Wirtanen was a close friend of Tove Jansson and a model for the Snufkin character, whose green hat is borrowed from Wirtanen. The first Moomin comic strips were published in October 1947 in Ny Tid. The series had to stop earlier than planned, however, as readers criticized it and especially the Moominpappa character for his bourgeois sympathies.
Wirtanen published two memoirs: Mot mörka makter (Against Dark Forces), and Political Memoirs. He also published several collections of aphorisms, and other literary works.
Wirtanen married dance artist Irja Hagfors in 1954. He died in 1979 in Helsinki.