Magan was not a popular choice for the position and several members of his previous IRA Army Council were not impressed by him but did not oppose his nomination outright.
According to J. Bowyer Bell, he "wanted to create a new Army, untarnished by the dissent and scandals of the previous decade", with "no shadow of a gangster gunman, no taint of communism, but a band of volunteers solely dedicated to reuniting Ireland by physical force".
[6] Tim Pat Coogan describes him as "priest-like - who had given all his money, time and thought to the IRA, a deeply religious man of the old-guard school of Irish Catholicism [and] when he was again interned in the Curragh during the 1950s Border Campaign he organised a flourishing branch of the Legion of Mary".
Coogan recounts that Magan's Sinn Féin submitted key political and economic policies for review by friendly clergy, "to ensure that they contained nothing contrary to Catholic teaching".
Unlike Seán Mac Stiofáin, Cathal Goulding, and Manus Canning, later jailed for the raid, Magan evaded arrest and managed to return safely to Ireland.
Magan was chief of staff at the commencement of the IRA's Border Campaign, codenamed Operation Harvest, which began on 11 December 1956.