He started woodchopping with his father, George Foster, in 1978, and between them they won the World 600 mm Double-handed Sawing Championship eleven years straight. He and his brother Peter Foster continued competing and winning this event for another ten years, until 1999, making David a world champion 21 years straight. The pair lost in 2000, but re-gained the championship in 2001, after which David's son Stephen took over as his woodchopping partner.
His other achievements in woodchopping include winning the Australian Axeman of the Year award nine times in a row; winning every major woodchopping event in Australia and New Zealand; becoming the first person in sporting history to have won 1000 championships; and been the only axeman to have ever won six out of seven championships at the Royal Sydney Show.
Foster has received several awards for his cultural, charitable and community activities. These include being awarded an Order of Australia Medal, a commendation from the then Governor of Tasmania Sir Phillip Bennett, and an Anzac Medal for services to the community. He also received a Tasmanian of the Year award in 1995, and was appointed a Director of the National Australia Day Council in 1998.
David Foster is often joined in his charitable quests by Launceston cricketer, David Boon. Both Foster and Boon, as well as then Premier of Tasmania Jim Bacon, also willingly allowed their famous moustaches to be shaved off for charity.
Foster has written a book called The Power Of Two.