Sayer joins the London Greenwich venue after 17 years at Manchester City Football Club where he was responsible for the Club’s matchday operations and hospitality as operations director.
He will now be responsible for corporate event hire at The O2's events space, as well as team-building events at Up at The O2.
Rebecca Kane, general manager of The O2, said: "We’re delighted to welcome Steve on board as we continue to grow the commercial aspects of The O2. He has an excellent track record of delivering successful operations with visibly impressive results."
Sayer added: "With so much to offer visitors, The O2 provides a fantastic new challenge and I’m thrilled to be joining the team."
The O2 has 18 venues including The O2 Arena, with a total capacity of 20,000 people theatre-style; The Open Space, with 5,500sqm of event space; and The Piazza, with 1,750sqm of event space.