Tuanku Sallehuddin was proclaimed as Tunku Temenggong of Kedah on 28 November 1981. He became one of members of the Council of Regency when his eldest brother, Sultan Abdul Halim Mu'adzam Shah, served as the Yang di-Pertuan Agong from 2011 to 2016, and chaired that Council after the death of his elder brother, Tunku Annuar, in 2014.