He is married to actress Guðlaug María Bjarnadóttir and they have three children.
Símonarson mainly writes for the stage and is one of the most respected and popular dramatists in Iceland.
[citation needed] He is a very versatile writer having also written numerous novels, collections of short stories and poetry and children's books.
His songs and lyrics for children have been released on records and CDs.
Símonarson has been on the board of the Icelandic Writers Union and the Society of Composers and Copyright Owners since 1985.