It is known for producing heavily milled wool fabrics such as melton and doeskin,[1]: 153  and supplying these to the British Army, most notably for the red coats worn ceremonially by certain British Army units, especially the Grenadier Guards, for whom Hainsworth is the exclusive supplier of scarlet wool cloth for tunics, navy blue for trousers, and grey for winter greatcoats.

"[4] Hainsworth makes fabric for the clothing industry, academic dress, for fire-retardant personal protective equipment, automobile, upholstery, bakery conveyor belting, historical re-enactment, baize for billiard tables and the casino industry, and for costume and staging.

[5] In 1900, the founder's grandson, with the same name, was running the mill when he suffered a head injury in an industrial accident and was treated at the Leeds General Infirmary, spending twelve weeks in the hospital's care.

[7][8] After reaching an early twenty-first century nadir, the British wool industry has seen increased demand for its product.

Thomas Hainsworth said the firm has learned from past mistakes, and that shareholders have told him to focus on reinvesting in equipment to remain competitive, instead of taking profits out of the business.