Rein was born in 1775. Rein's father was Henno and his mother was Pabbo. His paternal grandparents were Tõnn and Mari; his maternal grandparents were Tints and Liis. He had a brother and three sisters, named Peep, Tiiu, Ann and Katri. He had a half-brother and two half-sisters, named Jakob, Mai and Madli. He died at the age of 32 in 1807.