Hiwaizi will work on UK and global client assignments while collaborating with the agency's creative and technology functions.
At Chemistry, Hiwaizi worked with clients including Tassimo, Baileys and Emirates. He was previously the director of strategy at Fortune Cookie and the planning partner at Crayon.
His appointment follows SapientNitro's acquisition of the digital and direct marketing agency DAD in a £26 million deal earlier this month.
Nigel Vaz, the SapientNitro managing director, said: "Omaid has an exceptional pedigree in digital strategy born of rigorous insight. His origins as a pure mathematician and direct marketer allow him to build powerful arguments for ideas and make him an excellent addition to the SapientNitro strategy team."