Born in Bethnal Green on 27 March 1903 to a Jewish family, Mason moved to Leeds as a child, where he worked as a trolley boy for the London & North Eastern Railway.

[5] Mason met fellow Jewish boxer Philadelphian Harry "Kid" Brown at the Pioneer Sporting Club in New York on 15 January 1924, winning in a ten-round points decision.

He lost the British Welterweight title to Jack Hood on 31 May 1926, in a highly disputed twenty rounds decision in Kensington, England, and later unsuccessfully appealed against the official ruling.

[11] In his most widely publicized bout in Australia on 25 August 1928, Mason lost to Tommy "Nutty" Fairhall in a fifteen-round points decision at Sydney Stadium.

[11][14] In an important defence of his lightweight title on 29 April 1926, Mason drew with ring great Len Harvey at Royal Albert Hall in Kensington.

[16] Mason lost to future world welterweight champion Tommy Freeman on 18 August 1927, in a ten-round points decision at New York's Madison Square Garden.

In an important career bout, Mason lost to former world welterweight champion Joe Dundee on 28 May 1930, in a ten-round points decision at Madison Square Garden.

[18] Mason drew with well-known American boxer James "Red" Herring in a ten-round points decision on 29 July 1930 in Utica, New York.

[21] In November 1932, he fought Ernie Rice at the Royal Albert Hall with his British and European lightweight titles at stake, winning on points over 20 rounds.

[1][22] A run of defeats followed, culminating in the loss of his British welterweight title to Pat Butler in a fifteen-round decision in Leicester, England on 17 December 1934.

[25] Mason's last fight on 21 February 1937 was a third-round technical knockout loss to former world junior welterweight champion Harry "Kid" Berg at The Ring, in Southwark.