Simberg met his future wife, Anni Bremer, when he was her teacher at the Ateneum. They fell in love and were married in 1910. They had two children, Tom (1911) and Uhra Beata (1913). Simberg was an attentive and devoted father. The family lived in several places in Helsinki, including Luotsikatu 4, but they spent their summers at Niemenlautta, where a studio was built for Simberg.
The artist liked to portray his family, both with a camera and in his later paintings.