Overseeing 4,000 staff, Bloomfield will head internal comms in the build-up to the opening of Terminal 5, Europe's biggest construction project.
Bloomfield leaves the internal comms agency after eight years. He joins Heathrow in September and will report to director of comms Ben Morton.
He will be responsible for an in-house newspaper and the company intranet, and for encouraging friendliness to customers.
Bloomfield replaces interim director of internal comms Carl Williams, who has held the post for a year.