DUP leader Sir Jeffrey Donaldson said Mr Hilditch stepped down from his position today, having faced illness "with determination and dignity".
Sir Jeffrey said:“I want to thank David and pay tribute to him for his many years of public service. David was first elected to the Northern Ireland Assembly in 1998 and was one of only three of the class of 1998 remaining. His retirement marks the completion of a remarkable thirty-two years of public service to the people of Carrickfergus, East Antrim and indeed Northern Ireland."
Mr Hilditch served in local government from 1991-2008, with two terms as deputy mayor of Carrickfergus Borough Council and one year as mayor, 1997-98.
He was elected to the Assembly five times, in 1998, 2011, 2016, 2017 and 2022.
Sir Jeffrey added: "He has been a dedicated, consistent and active member of our party for many decades, always helping and supporting colleagues locally and throughout Northern Ireland.”
"David has faced his illness with determination and dignity. I know the thoughts, prayers and best wishes of colleagues not just in the DUP, but across the political spectrum are with him as he steps down from public life.”
East Antrim DUP MP Sammy Wilson said that since being elected to the council in 1991, Mr Hilditch was known as ‘Mr DUP’ in the Carrick area.
The MP added: “He is well connected to his constituents through his involvement in the Loyal Orders, Football Clubs and community groups and from his previous job as a postman.
"He won huge respect which was reflected in the votes he achieved at Council and Assembly level. Despite fighting serious illness Davy never faltered in his dedication in the responsibility that he had as a public representative and only withdrew when it became apparent his illness was preventing him from carrying out those duties."
East Antrim MLA Gordon Lyons also paid tribute. “ No-one could knock doors in Carrickfergus and not hear many stories from people who Davy has helped over the years,” he added.