1997–2010: The District of Lisburn wards of Ballinderry, Ballymacash, Ballymacbrennan, Ballymacoss, Blaris, Derryaghy, Dromara, Drumbo, Dunmurry, Glenavy, Harmony Hill, Hilden, Hillhall, Hillsborough, Knockmore, Lagan Valley, Lambeg, Lisnagarvey, Maghaberry, Magheralave, Maze, Moira, Old Warren, Seymour Hill, Tonagh, and Wallace Park, and the District of Banbridge wards of Dromore North, Dromore South, Gransha, and Quilly.

2010–2024: The City of Lisburn wards of Ballinderry, Ballymacash, Ballymacbrennan, Ballymacoss, Blaris, Dromara, Drumbo, Harmony Hill, Hilden, Hillhall, Hillsborough, Knockmore, Lagan Valley, Lambeg, Lisnagarvey, Maghaberry, Magheralave, Maze, Moira, Old Warren, Seymour Hill, Tonagh, Wallace Park, and part of Derryaghy; the District of Banbridge wards of Dromore North, Dromore South, Gransha, and Quilly and the Ballynahatty and Edenderry parts of the Belvoir ward of the City of Belfast.

2024–present: The District of Armagh, Banbridge and Craigavon wards of Aghagallon, Donaghcloney, Dromore, Gransha, Magheralin, and Quilly; and the District of Lisburn and Castlereagh wards of Ballinderry, Ballymacash, Ballymacbrennan, Ballymacoss, Blaris, Dromara, Harmony Hill, Hilden, Hillhall, Hillsborough, Knockmore, Lagan, Lagan Valley, Lambeg, Lisnagarvey, Maghaberry, Magheralave, Maze, Moira, Old Warren, Ravernet, Wallace Park, and White Mountain.

He succeeded James Molyneaux who had represented the seat for the UUP since the 1983 general election and previously sat for the old South Antrim constituency which covered much of the same area.

This seat saw a swing towards the Alliance Party of over 17%, and the largest decrease in vote share for the DUP at the 2019 general election.