Chilwan joined DIB in 2008 and assumed his current position in July 2013. In the first half of 2024, DIB reported assets exceeding $87.9 billion, a net profit of $920 million, and a workforce of more than 9,000 people. In July 2024, DIB led a landmark $3.25 billion financing transaction for GEMS Education. Chilwan is also the chairman of DIB Bank Kenya Ltd, and sits on the boards of Deyaar Development, and the Liquidity Management Centre in Bahrain.