Gregg married his first wife, Mavis Markham, at St James's Church,
Doncaster, in 1957, while still a Doncaster Rovers player. Mavis died of
cancer in 1961. On 2 July 1965, Gregg married Carolyn Maunders at St Mary's Parish Church, Rostherne. They had four children. Gregg's uncle was the grandfather of fellow footballer
Steve Lomas, who played for clubs including
Manchester City and
West Ham United, and managed
St Johnstone and
Millwall. Gregg once owned the Windsor Hotel in the town of
Portstewart, on the north coast of County Londonderry. Gregg played for an under-18 team from Coleraine in a Ramelton Cup match during the 1950s. In May 2011, Gregg agreed to go back to
Ramelton,
County Donegal where he spent an evening, alongside
Jobby Crossan, with local people in Ramelton Community Hall. Gregg celebrated his time at Old Trafford on 15 May 2012 with a testimonial organised by John White and John Dempsey from the George Best Carryduff Manchester United SC. The testimonial featured Manchester United playing an Irish League Select XI managed by
Martin O'Neill and
David Jeffrey. The match ended 4–1 to Manchester United. Gregg died on 16 February 2020, aged 87, after several weeks of illness, at the
Causeway Hospital in
Coleraine, County Londonderry, Northern Ireland. ==Career statistics==