Along with most of those involved in the coup of April 1967, he was an officer of the Greek Army. At the time he held the rank of Lieutenant General and was appointed Chief of the Army General Staff following the coup. He was responsible, at least officially, for the Army Decree Nr. 13, which banned the musical works of Mikis Theodorakis. In the failed royal counter-coup of 13 December 1967, Angelis remained loyal to the junta, and was rewarded with promotion to full General and appointment as Chief of the Armed Forces Command. On 21 April 1967 Angelis passed a series of laws limiting protest, including a ban on public gatherings of more than five people, a ban on all private gatherings of a political nature, a ban on propaganda against the generals and a ban on civilians holding guns. Personally loyal to junta principal Georgios Papadopoulos, Angelis was chosen by the latter as his Vice President when he abolished the monarchy and declared Greece a Presidential Republic on 1 June 1973. Angelis served in this post until 25 November 1973, when Papadopoulos lost power to a hardliner coup.