He is stated to have founded his business in Northampton by 1858 (though 1862 is the first certain date for his presence in the town), a year after the first two industrialized boot and shoe factories had just been built, when he established G.L.Michel, a company of leather merchants, and eventually shoe-machinists. He was one of a small number of the founders of the industrialized shoe industry in Northampton (along with fellow Jew, Samuel Isaac). He married Elizabeth Harris in London, in 1862 and became a Northampton Freemason in 1863. He became a naturalized British citizen in 1880. Michel's major trade was supplying upper leather to shoe manufacturers and he became one of the largest suppliers in Northampton and county.
Michel was one of the founders of the modern Jewish congregation in Northampton. It started when he gathered the Jews in Northampton to worship at rooms in his home in Newlands, from 1885. Most of its members worked in the shoe and leather industry, or as tailors. Many were compelled to work on Saturdays, and sometimes they could not muster a minyan for services (the minimum ten men), as they were all labouring. He and others established the Northampton Hebrew Congregation, in 1888. He later secured a synagogue (a converted 'iron church') in Overstone Road in 1890 and a separate Jewish section in the municipal cemetery in 1902.
Michel was a leading man in the town's industrial life. Towards the end of his life he was also acknowledged and respected as the most senior Free Mason in Northampton.