Reng in his new role will report into managing director Jon Davie and will oversee all digital production within the agency, working across clients including Coca-Cola, BT, The Economist, Bupa, National Trust, Yahoo! and Macmillan Cancer Support.
He will also work closely with chief technology officer Marc Parnell, who heads up the agency’s German office in Cologne.
Before joining TBWA, Reng was head of digital at Australian creative agency Colman Rasic, with earlier stints working on web projects for The Financial Times in London and Fairfax Media in Australia.
Davie said: "Rob brings both technical expertise and creative agency experience to Zone.
"His appointment completes our agency senior management team, which now boasts fantastic experience across the board. He has inherited a brilliant team of developers and will ensure we continue to deliver elegant, effective and award-winning technical solutions for our clients."
During his 15 years in the industry, Reng has worked for clients including Nissan, PlayStation and GlaxoSmithKline.
Last year Reng helped TBWA win a Cannes Lions for the 'My car is your car' campaign for NRMA Insurance and the IAB Creative Showcase for the Nissan 'Zen to Z' campaign.
Follow Matthew Chapman at @mattchapmanUK