MacMillan was previously the Executive Chairman of
Alliance Atlantis. Macmillan co-founded
Atlantis Films in 1978. In its early years, Atlantis was primarily a film and television production house, winning an Oscar in 1984 for its short film
Boys and Girls and an Emmy in 1992 for
Lost in the Barrens. Atlantis was also nominated for an Oscar for
The Painted Door. In 1993, Atlantis became a broadcaster with the launch of its first network,
Life Network. In 1998, Atlantis acquired Alliance Communications and became Alliance Atlantis. Under Michael's leadership, the company operated 13 Canadian television networks including
HGTV Canada,
Showcase Television,
History Television and
Food Network. The company also distributed and produced movies and television programs including the hit series
CSI: Crime Scene Investigation. In 2007, Macmillan retired from Alliance Atlantis when he sold Alliance Atlantis to
Canwest and
Goldman Sachs. In 2011, MacMillan returned to broadcasting by launching upstart media company
Blue Ant Media, a privately held Canadian media company that creates and distributes engaging content in categories that span lifestyle, travel, music and entertainment. The company owns specialty channels
Cottage Life,
Travel + Escape,
Makeful, and
A.Side TV along with four premium, commercial-free channels
Smithsonian,
Love Nature,
HIFI HD,
BBC Earth and their companion websites. Its digital publishing division produces content for web, mobile and monthly tablet magazines for AUX and Travel + Escape. Cottage Life Media is a division of Blue Ant Media, publishers of Cottage Life and Cottage Life West and producer of various consumer shows. Blue Ant Media was named
Marketing Magazine’s 2012 Media Player of the Year. MacMillan is Co-founder and Chairman of Samara, non-partisan charitable organization that works to improve political participation in Canada. Samara was formed out of a belief in the importance of public service and public leadership. It is named after a
samara, the winged seed that falls from the maple tree. Through its projects, it hopes to strengthen the health of Canada's democracy and encourage others to do the same. He is also the co-founder of the Open Roof Festival. Additionally, Macmillan is the co-founder and co-owner of Closson Chase, a vineyard and winery in
Prince Edward County, Ontario. Closson Chase produces
pinot noir and
chardonnay wines and was one of the pioneers in establishing Prince Edward County as a new location for winemaking in Canada. ==Personal life==