Musa Keita was referred to (and is most commonly found) as Mansa Musa in Western manuscripts and literature. His name also appears as Kankou Musa, Kankan Musa, and Kanku Musa. "Kankou" is a popular Manding female name, thus Kankou Musa reads "Musa whose mother was Kankou".
What is known about the kings of the Malian Empire is taken from the writings of Arab scholars, including Al-Umari, Abu-sa'id Uthman ad-Dukkali, Ibn Khaldun, and Ibn Battuta. According to Ibn-Khaldun's comprehensive history of the Malian kings, Mansa Musa's grandfather was Abu-Bakr Keita (the Arabic equivalent to Bakari or Bogari, original name unknown − not the sahabiyy Abu Bakr), a brother of Sundiata Keita, the founder of the Malian Empire as recorded through oral histories. Abu-Bakr did not ascend the throne, and his son, Musa's father, Faga Laye, has no significance in the History of Mali.
Mansa Musa Keita came to the throne through a practice of appointing a deputy when a king goes on his pilgrimage to Mecca or some other endeavor, and later naming the deputy as heir. According to primary sources, Musa was appointed deputy of Abubakari Keita II, the king before him, who had reportedly embarked on an expedition to explore the limits of the Atlantic Ocean, and never returned. The Arab-Egyptian scholar Al-Umari quotes Mansa Musa as follows:
The ruler who preceded me did not believe that it was impossible to reach the extremity of the ocean that encircles the earth (the Atlantic Ocean). He wanted to reach that (end) and was determined to pursue his plan. So he equipped two hundred boats full of men, and many others full of gold, water and provisions sufficient for several years. He ordered the captain not to return until they had reached the other end of the ocean, or until he had exhausted the provisions and water. So they set out on their journey. They were absent for a long period, and, at last just one boat returned. When questioned the captain replied: "O Prince, we navigated for a long period, until we saw in the midst of the ocean a great river which was flowing massively.. My boat was the last one; others were ahead of me, and they were drowned in the great whirlpool and never came out again. I sailed back to escape this current." But the Sultan would not believe him. He ordered two thousand boats to be equipped for him and his men, and one thousand more for water and provisions. Then he conferred the regency on me for the term of his absence, and departed with his men, never to return nor to give a sign of life.