Complex sentence: The brand name, J. C. Higgins, was based on a real person, John Higgins, a Sears employee from 1898 until his retirement as head bookkeeper in 1930.
Split into simpler sentences: The brand name, J. C. Higgins, was based on a real person, John Higgins who was a Sears employee. He worked with the company until his retirement as head bookkeeper in 1930.