István was born in 1800. István's father was Tétsi Sámuel and his mother was Pándi Anna. His paternal grandfather was Tétsi Sámuel and his paternal grandmother is Tóth Anna. He had two brothers and a sister, named Sámuel, Sándor and Julianna. He was the second youngest of the four children. He died at the age of 94 in 1894.