His father, James Butler, was boxing correspondent at the Daily Herald, and introduced Frank to the sport at an early age.
As a child Frank watched such stars as Augie Ratner, Mickey Walker and Georges Carpentier at their training camps, and saw the fights of leading British boxers such as Ted "Kid" Lewis, Ernie Rice and Harry Mason while perched between two press seats – one occupied by his father, and the other, as he remembered it, by either Charlie Rose or Fred Dartnell – themselves leading boxing correspondents.
Before he was 10, Butler had watched innumerable boxing matches at notable venues such as the National Sporting Club, Premierland, the Blackfriars Ring, the Royal Albert Hall and Olympia.
He was encouraged and helped enormously by Trevor Wignall, the newspaper's main sports columnist at the time, and also by the Express Editor Arthur Christiansen.
Butler soon became the newspaper's chief boxing writer and columnist, and in 1941 – at the age of 24 – was appointed sports editor at the Sunday Express (the youngest person to hold that position).