Willis, who was an associate director at IPT, takes on the role of director of the media agency team at eCircle.
He moves across with IPT colleagues Robyn Bauchop, who spent three years at IPT, and has been made senior project manager, and Paul Wells, formerly a senior sales consultant at IPT, who will take on the same role at eCircle.
The agency said Willis would be responsible for its lead generation, email list rental, mobile and market research operations. Prior to joining IPT, he held roles at PDV and Experian.
Bauchop will oversee media campaigns and team management, account handling and managing customer support processes at eCircle.
Paul Wells, will be responsible for driving new business.
Volker Wiewer, chief executive officer at eCircle, said: "We've worked hard to build a company of experts that clients are keen to work with.
"For me, there is no greater validation of our position in the core UK market than seeing staff come to us from more established, long-standing competitors."
The agency launched a lead generation site, last month to provide brands with highly targeted consumer insight.