Weir attended Bangor Grammar School and graduated from The Queen's University of Belfast in Law and Accountancy.

Weir was later expelled from the Ulster Unionist Party for refusing to support the re-election of David Trimble as First Minister of Northern Ireland.

In the 2005 Westminster election Weir was a DUP candidate for North Down, but lost to Sylvia, Lady Hermon, of the Ulster Unionist Party.

It was announced on 14 October 2022, that as part of the 2022 Special Honours, Weir would receive a life peerage, sitting for the Democratic Unionist Party.

[7] Weir reported in November 2021 that one of his toes had been amputated as a result of an infection following a type 1 diabetes diagnosis.