In his new role Syal will oversee the digital aspects of Walker Media's campaigns for clients including Dixons, KFC, Dyson and Travelex.
At Diffiniti, Syal managed the Dell account across 11 markets. He began his career in 1997 at Carat in broadcast buying and joined EHS as an interactive manager two years later. Syal returned to Carat Interactive in 2000.
Separately, Ben Buxton, an account manager at Starcom Digital, is joining Walker-i as an account manager.
Buxton, who previously oversaw 20th Century Fox's account at Starcom, started his career as a planner and buyer at PHD.
Christine Walker, Walker Media's chairman, said: "With the appointment of Syal to lead this company and Buxton to strengthen our operations, I'm confident we are building a resource to match our clients' expectations."