Cogan will lead McDermott's global projects and infrastructure practice, working out of London and the firm's new Houston office.
McDermott's new head of London and Europe Doron Ezickson said Cogan's time would be divided equally between the two cities. He added: "Critical to John's consideration to join the firm was the existence of a very strong London practice as a key location for clients in different parts of the globe."
At Akin Cogan has had a base office in London since 2003. He specialises in international exploration, extraction, processing and transportation, focusing on Latin America, Europe, Asia and the Middle East.
McDermott launched in Houston in February, hiring three energy partners from Bracewell & Giuliani as well as King & Spalding corporate partner James Wilson.