 Johnson switched fighters and seconded Mendoza against Humphries at Doncaster on 29 September 1790, and again in a contest against Warr near Croydon in May 1792.Similarly, he acted as second for Hooper when he fought George Maddox at Sydenham Common on 10 February 1794 and for Tom "Paddington" Jones at Blackheath on 10 May 1794.Other occasions when he acted as second include for John Jackson (near to Croydon, 9 June 1788; and against Mendoza at Hornchurch on 15 April 1795), and Joe Ward (at Hyde Park, date unknown).