Maples joined Microsoft from Maiden Outdoor (now Titan) in May 2007 as managing director of its network business.
He was promoted to the role of sales director at Microsoft Advertising in July 2008 and since 2009 has been responsible for all display, network, search ad serving and analytics business in the UK.
Maples said: "I only made the decision at Christmas. I have no career plans yet. I am just looking forward to spending more time with my children.
"I've enjoyed my time at Microsoft and wish them all the success in the world."
Maples started his career at the first ever ITV sales house TSMS before joining Channel 4 as part of the launch team when the channel became commercially independent in 1993.