His arrival coincides with the promotion of Chris Ricketts to sales director, digital. The pair will report to Jim Freeman, group sales and trading director.
Buckley, a former head of radio at ZenithOptimedia, joined Microsoft in 2012 from i-level where he was head of trading. Ricketts has worked at TMG since 2000.
Buckley said: "After six wonderful years at Microsoft, I am looking forward to a new challenge at one of the most iconic and progressive UK news brands.
"The chance to be involved in the digital future of TMG is a great opportunity and I can't wait to get started."