Siby was born as the son of Simon from Arackal family at Monippally and Pennamma from Mattappallil family in Karimkunnam. Siby was born in August 1959
He married Geetha, daughter of Luckachan from Thekkumkattil family in Kidangoor. Their marriage was on January 22, 1990 in Sacred Heart Church, Monippally. Children of Siby and Geeetha are Neethu, Nithya, and Nitha.