[2][3] Glendinning was a founder of the Alliance Party of Northern Ireland, and left teaching in 1973 to become its full-time political organiser.
[3][4][5] In 1976, Glendinning returned to teaching, working at the Royal Belfast Academical Institution,[3] although he remained politically active, campaigning for the Alliance Party into the 1980s,[1] and presenting a submission to the New Ireland Forum in 1983.
[6] He also began writing short stories, some of which were published in the Irish Times, as a result of which he won the Hennessey Award.
These early works included The Artist, Condemning Violence, Culture Vultures, Faith, Mumbo Jumbo and Stuffing It.
[1][3] In 1991, his Donny Boy won "Best New Play" at the inaugural TMA Awards,[7] and this success inspired him to again quit teaching, this time to become a full-time writer.