Chambers has been an Ulster Unionist Party (UUP) Member of the Northern Ireland Assembly (MLA) for North Down since 2016.

[1] Chambers was elected to North Down Borough Council in a by-election on 17 April 1991 as an Independent, representing the Ballyholme and Groomsport electoral area.

[8] He contested North Down as an independent at each subsequent Assembly election, receiving 3.7% of first preferences in 1998,[8] 3.5% in 2003,[8] 3.7% in 2007[8] and 6.3% in 2011.

[11] Following the 2022 Assembly election, he served in the chair as acting Speaker of the Northern Ireland Assembly, during attempts to restore the Northern Ireland Executive, following the Democratic Unionist Party (DUP)’s decision to withdraw from the executive in February that same year.

He warned that cancer services in Northern Ireland are "spiralling into ever deeper crisis due to ongoing political impasse.