Born in Morocco, his father was a large shareholder in an insurance company that Othman would take over in 1988; turning it into RMA Watanya. After purchasing the insurance company, Benjelloun expanded the business venture into the banking industry. His banking enterprise, the BMCE Bank has its presence felt in at least 12 countries in Africa after it purchased the Mali-based Bank of Africa.
Othman received an education in engineering at the École Polytechnique Fédérale de Lausanne in Switzerland. During the 1960s and 1970s, Othman would make strategic alliances with global automobile manufacturers Volvo and General Motors. He is also the chairman of Meditelecom along with being associated with Telefónica and Portugal Telecom.