Metelo comes to the floating turbine developer from EDP Renewables North America, where he was executive vice president and CFO.
While employed by EDP, Metelo managed several large mergers and acquisitions, including the purchase of Horizon Wind Energy from Goldman Sachs.
The company said that it has brought Metelo onboard to deal with its "transition from a start-up to a mature operating company".
Principle Power has developed the WindFloat floating offshore platform, which it hopes to deploy on a large scale in deeper waters than current offshore projects.
A prototype fitted with a Vestas V80 2MW turbine has been operating off the coast of Portugal since 2012.
Earlier this month, Principle Power was granted an additional $47 million in US government funding for the construction of a 30MW project near Oregon, in the deep Pacific Ocean. It will feature the semi-submersible foundation and five Siemens 6MW turbines.
EDP worked on the development of the prototype project with Principle Power.