His artistic training began in 1930 when he enrolled at Salford Art School, where his abilities were soon recognised and he was awarded the Heywood Medal for Best Student.
He later cited poster artists Adolphe Mouron Cassandre and Edward McKnight Kauffer as major influences.
His bold, simple style was well-suited for the workplace safety posters he produced for the Royal Society for the Prevention of Accidents throughout his career.
The start of World War II in 1939 effectively marked the end of Eckersley's partnership with Lombers, as they joined different military services and there was a decline in demand for commercial advertising.
This led Eckersley to create posters for the Royal Society for the Prevention of Accidents (RoSPA), aimed at workers in factories and industrial settings that often supported the military in someway.
After the war commissions for government posters reduced and, due to rationing and financial strain, commercial advertising was still restricted.
Notable graduates who benefitted from Eckersley's tutelage include illustrator Ralph Steadman, advertising's John Hegarty and art pathfinder Charles Saatchi, graphic designers Michael Peters and Howard Milton.
The range of companies who commissioned both the Eckersley-Lombers partnership and Eckersley individually reflects the wide appeal of their/his striking designs: Shell-Mex & BP, BP, the BBC, London Transport, the Ministry of Information (from 1946 the Central Office of Information), the Royal Society for the Prevention of Accidents (RoSPA), Austin Reed, the General Post Office, Gillette, The United Nations Children's Fund, the World Wide Fund for Nature, the National Business Calendar Design Awards, Cooks, British Leprosy Relief Association, National Bus Company, London College of Printing, Guinness, the Wildscreen International Wildlife Film and Television Festival, the Inner London Education Authority, City & Guilds of London Institute, Imperial War Museum and advertising agency WS Crawford.
He also designed posters for events and seasons for example, one for a seminar Eckersley gave at the Grafiska Institute, Stockholm, Sweden, in 1960.