Imam 'Ali ( pbuh ) was the first male to embrace Islam. Sharh Nahj al-Balaghah , ibn Abi al-Hadid al-Mu'tazili, 13:224
He himself declares: "I started worshipping Allah nine years before anyone else in this nation started worshipping Him except Prophet Muhammad ( pbuh&hf )." Khasa'is Amir al-Mu'minim , al-Nisa'i, 13:39; refer also to Tarikh al-Tabari 2:316 and 5:17 to see when other companions embraced Islam