Mu'awiya was son of Abu Sufyan, a leader of Banu Umayyah clan which was one of the clans of Quraish tribes. This clan came into existence as successors of Abde Shams, the brother of Moulana Hashim. Mu'awiya grew up in a family known to be cunning, worldly, materialistic, and power hungry. Mu'awiya became Muslim only when Prophet Muhammad (pbuh) triumphed over Mecca. Those who became Muslim in this manner were called Tulaqaa', (a term scornfully used for the disbelievers who became Muslims to save their lives). Mu'awiya, his father Abu Sufyan, his mother Hind, and his brother Yazid son of Abu Sufyan were all Tulaqaa'; Mu'awiya never forgot this stigma for the rest of his life; he could never shake it from his mind, thus a feeling of malicious vengeance always existed in his heart.
Omar La'een, appointed Mu'awiya's brother, Yazid son of Abu Sufyan, as the Governor of Syria when the Muslims captured that territory from the Byzantines. Within a few years, Yazid son of Abu Sufyan died of a disease, and Omar appointed Mu'awiya in his brother's place as the Governor. (This is considered as one of his plots to set-up a Banu Umayyah Rulership on the Mulim Ummah, as Banu Umayyah were well known for their hate for Banu Hashim). Upon coming to power, Mu'awiya took advantage of the rich public treasury of Syria using it personally to buy favors and influence people. Thus he built a large base of support among some tribes, almost to the fanatic level. He used this to his advantage in later years to form a network of informants (spies) against Ahlul Bayt (a.s.) and their devotees.