Mr Shea has worked at Fidelity for 26 years and is currently head of Fidelity's platform operations and customer services.
He will take over from Hugh Mullan, who assumed interim responsibility for FundsNetwork in June following the departure of David White.
Mr Shea has previously worked in senior roles for the firm in Bermuda, Hong Kong, India and Taiwan.

Mr Mullan, managing director of UK direct-to-consumer and retail, said: "I am pleased to announce the appointment of such an experienced, long-serving and loyal Fidelity manager to the important role of head of FundsNetwork.
"Pat has exactly the right blend of skills, knowledge and experience to lead FundsNetwork through the exciting and challenging period ahead as we move towards the implementation of the RDR and beyond.
"FundsNetwork will continue to be a market-leading and innovative business. Pat's deep and broad knowledge of intermediary products, servicing and platform operations makes him ideally placed to lead the business forward."
FundsNetwork was launched in 2000 and has 1,200 funds from more than 70 providers.