al-Sa'di was born in the city of Unayzah, al-Qassim, Saudi Arabia in 1889/1307AH. His father, Nasir al-Sa'di, was an imam and preacher in a mosque in the Unayzah. His mother, Fatimah bint Abdullah al-'Uthaymeen, died when he was four years old, and his father passed away when he was seven. He was initially cared for by his father's second wife and was later transferred to the guardianship of his oldest brother, Hamad ibn Nasir al-Sa'di. He completed his memorization of the Qur'an by the age of eleven and then pursued religious education from the scholars in his locality. In his teenage years, his fellow students began to refer to him for help in their studies.