McGrady entered politics in 1961[2] as an Independent Nationalist councillor on Downpatrick Urban Council, serving as chairman from 1964 until the council was replaced by Down District Council in 1973.
In 1970 he became a founder member of the Social Democratic and Labour Party (SDLP), later serving as its first chairman (from 1971–1973). He sat on Down District Council from 1973 to 1989, serving as chairman from 1974–1975 and was also elected to all three regional assemblies in 1973, 1975 and 1982 representing South Down. In the 1973 power-sharing executive he was appointed as Head of the Department of Executive Planning and Co-ordination, serving from January to May 1974.
In Westminster elections he contested South Down unsuccessfully in 1979, 1983 and at the by-election of January 1986, losing on each occasion to Enoch Powell, the sitting MP. He succeeded at the fourth attempt in the general election of 1987 and held the seat until retiring in 2010. His tenure was briefly threatened in the mid-1990s when the Boundary Commission suggested merging much of his constituency with the neighbouring Newry and Armagh constituency to form a new 'Newry and Mourne' constituency. This was overturned during a local review, which preserved his seat and actually removed more Unionist sections such as Dromore. McGrady's support held solid over the years despite talk of a slippage, and this was reinforced in the 2005 Westminster election with his re-election to the House of Commons.[citation needed]
