He was educated at St Peter's College in Birmingham before beginning work as a publicity copywriter and served for five years in the Royal Electrical and Mechanical Engineers during the Second World War.
Initially seen as a compromise candidate (after the rebellion against Chesterton, no one was willing to take the post), he soon set about trying to modernise the party and clashed with John Tyndall and Martin Webster over the issue, who had backed the O'Brien candidacy because they thought erroneously that he could be easily manipulated.
[5] During the resulting struggle O'Brien briefly departed from the scene to go on honeymoon and during his absence the pro-Tyndall contingent made moves to expel a number of his supporters.
Although the NIP initially looked like it might challenge the NF, Tyndall's party was galvanised by the arrival in Britain of Uganda's Asian population, who had been expelled by Idi Amin.
His involvement with the This Week documentary on ITV about the NF (Thames Television, ITV, September 1974 – where he was also interviewed at length about the party he left whilst its chairman) caused immense damage to the National Front and instigated fury within the party's ordinary membership that they had not been made aware as to the full extent of the neo-Nazi pasts and continuing links of the likes of Tyndall and Martin Webster.