[2] In 1969 he was elected to the Parliament of Northern Ireland for Belfast Pottinger[3] as an 'O'Neill Unionist' supporting the reform proposals of the then Prime Minister.
In 1973 he was elected to the Northern Ireland Assembly for Belfast East, as a Unionist pledged to support the former Prime Minister Brian Faulkner.
In March 1982, Cardwell was questioned by police in relation to his visits to Kincora Boys' Home, which had seen a child sex abuse scandal.
The Hughes report into the scandal noted that Cardwell told the police of one conversation with the Belfast Town Clerk, who had mentioned an imprecise allegation of homosexual conduct (which at that time would have been illegal in Northern Ireland), but he said that no formal complaint had ever come his way.
[8] The Josh Cardwell Centre, providing rehabilitation services in East Belfast, was named in his honour, but this closed in 2007.