The appointment of Miron, 38, is the latest in a series of changes at Associated that have ushered in a new generation of senior management.
Last year, Mike Anderson, the former managing director of Metro, replaced Sally de la Bedoyere as the managing director of the Evening Standard.
Miron, widely dubbed "golden boy" because of his strong relationship with the Daily Mail's proprietor, Lord Rothermere, was previously responsible for Associated New Media, Ireland on Sunday, Cube and the free ad paper Loot. He will continue to oversee the operations of Ireland on Sunday.
The Mail on Sunday has already made a series of changes to its senior ad sales line-up. It recently replaced its ad director Sue Dear with Simon Davies. Davies then hired Chris Willis from Guardian Newspapers in a senior role.
Miron started his career at Safeway before joining Associated in 1988, rising to ad manager for You magazine and Night & Day on The Mail on Sunday.
He left Associated in 1998 to take the role of commercial director for The Independent and Independent on Sunday before returning to Associated last year to revamp Loot and Associated's new-media activity.
Part of Miron's challenge will be to sustain The Mail on Sunday's circulation.
In September, its sales were down 1.8 per cent year-on-year to 2,266,088.
Miron said: "I spent ten good years at The Mail on Sunday earlier in my career. It's a marvellous job and I am looking forward to the challenge."
Since rejoining Associated, Miron, who has a seat on the Associated board, appointed the Financial Times' ad director, Claire Payne, as the managing director of Loot and Andrew Hart as the managing director of Associated New Media.