Stephenson was poached by the insurance giant from a role at agency Prosek Partners, which he joined after his time at Royal Mail.
He will start in the role today and oversee all external communications, internal communications and public affairs.
Working closely with CEO Paul Evans, he will report to Cheryl Toner, group marketing and communications director.
Stephenson has spent the last year working as MD for the New York based agency Prosek, and will remain advisor to the CEO.
He has previously held senior positions within leading PR agencies Smithfield Consultants and Citigate Dewe Rogerson.
He also spent four years on the Board of the Conservative Party and became the youngest ever President of the Conservative Convention, chairing the 2004 Party Conference.
Stephenson said: ‘I am especially attracted to the company’s reputation for adopting progressive ideas. AXA remains the only insurance company to have banned referral fees from personal injury lawyers and has taken a lead on the "compensation
