His training covered the manufacture of textile machinery including carding engines, jennies, and water frames.

On the completion of his apprenticeship in 1791, he moved to Manchester and went into a long-lasting partnership with James McConnel, a nephew and former apprentice of Cannan, to manufacture textile machinery and undertake cotton spinning.

Kennedy was a skilled and inventive engineer and is credited with devising a crucial improvement to fine-spinning machinery, called double speed, which enabled much finer thread to be manufactured.

In 1795 McConnel and Kennedy, now financially independent, moved to a new factory in the same Canal Street, where they remained for six or seven years.

Kennedy died in 1855 at Ardwick Hall, Manchester, and was buried at the nearby Rusholme Road cemetery.