Moran, who left Lida in September last year, will oversee TCA's 25-strong creative department, presiding over a client list that includes American Express, Argos, Warner Bros and The Economist.
He will work closely with James Champ, the agency's planning director, and report to its chairman and founder, Robert Prevezer, and its chief executive, Adam Leigh.
Moran had spent three-and-a-half years at Lida, during which time he helped the agency pick up work from Boots and The Carphone Warehouse.
Before that, he was a creative director at Partners Andrews Aldridge, where he created campaigns for brands including Vodafone, Lloyds TSB and the RAC.
Moran said: "TCA has a strong independent heritage and has not sought fame at the expense of its clients, which is refreshing in this industry. I am greatly looking forward to helping the agency build on this fantastic track record."
TCA has also hired Publicis Dialog's Jenny Phillips as its client services director.