Sandgren and Karolina Adolfsson, who gave their son a poor but happy childhood.

Their son Gustav had since childhood, both heard and played on the fiddle—a musical instrument which he handled with skill throughout life.

Together with Harry Martinson, Artur Lundkvist, Erik Asklund and Josef Kjellgren, he formed the literary group Fem unga ("Five young ones").

The last name Linde referred to the croft where he stayed in the summer of 1933, located about a kilometre southeast of Norrvrå station in Hölö, Södermanland.

In 1945 he left his wife for Ria Wägner, with whom he lived for forty years at Lidingö, Stockholm.