In 1977, he helped organise the "Gateshead Fun Run", a pioneering running event. In 1981, Foster founded the Great North Run, an annual half marathon from Newcastle upon Tyne to South Shields. The race became the biggest running event in the UK, and one of the biggest half marathons in the world. By 2014, the race had been run by over 1 million competitors, the first IAAF event to pass this milestone. Foster ran in the 2003 event for the first time in many years, after being challenged to do so by radio presenter Ray Stubbs.