Nama Sultan Muhammad Syah sebelum memeluk agama Islam ialah Raja Kecil Besar. Metos pengislaman Sultan Muhammad Syah menggambarkan bagaimana baginda telah diajar mengucap dua kalimah syahadah dan baginda dikhatankan dalam mimpinya. Baginda merupakan seorang yang alim serta amat patuh kepada ajaran Islam. Selain itu, baginda juga adalah seorang yang beretika dan berdisiplin tinggi. Ini dapat dilihat daripada pembaharuan adat istiadat yang telah diperkenalkan dan cara baginda memuliakan para tetamunya yang datang dengan penuh adat istiadat kebesaran diraja. Disebabkan sikapnya, baginda telah dapat membentuk hubungan diplomasi dengan beberapa buah kerajaan di Nusantara. Walau bagaimanapun, Sultan Muhammad Syah juga mempunyai beberapa sifat negatif seperti bersikap pilih kasih terhadap kedua anaknya, iaitu Raja Kasim dan Raja Ibrahim. Baginda lebih menyayangi Raja Ibrahim kerana berasal dari keturunan puteri raja. Manakala Raja Kasim hanya dari keturunan bangsawan.

Also known as Seri Maharaja, sultan Muhammad Syah changed his name when he embraced Islam. He was a pious ruler and adhered closely to the rules of Islam. This reverence made him a highly ethical and disciplined ruler. Sultan Muhammad Syah introduced new customs, changed some old customs and always treated his guests with honour, a sign of the disciplinarian that he was. Due to his credibility, Malacca managed to form diplomatic ties other Sultanate and government in the Nusantara. However, being human, Sultan Muhammad also had his weakness. One of them was his favor feelings towards one of his sons. He had two sons, Raja Ibrahim dan Raja Kasim. Although both were his own, he always favored Raja Ibrahim whose mother was a princess from Rokan, which means that Raja Ibrahim was a true Royal Prince (anak Gahara) where Raja Kasim whose mother was only a nobleman’s daughter, was not given the same favor.