Kobi, son of Flora and Eliezer Smilg, was born on May 30, 1986 in Rehovot. Brother to Esther, who was five years old when he was born. He was educated in his hometown, at the Weizman elementary school, and at the Katzir high school. In addition to his studies he dealt in sports: tennis, martial arts, and especially basketball, as part of Maccabi Rehovot.