One person that Malcolm X worked for in Mason, Michigan, was Dr. Gertrude O'Sullivan (http://brothermalcolm.net/mxtimeline.html). Malcolm was a chauffeur and houseman for Dr. Sullivan. There was not much information for when he started and stopped working for Dr. O'Sullivan, or for how his overall working experience was.
[Updated Aug 18, 2017 by John Aerni-Flessner]
Dr. O'Sullivan was born Jan 24, 1866 in Bradford, PA as Margaret Dart. She moved to Webberville in Ingham County, MI as a child. Her family later moved to Mason where her father was elected Sherriff and owned a lumber yard and mill. She married for the first time in 1887. Dr. A.B. Campbell was her first husband and she assisted him in his practice, serving as receptionist and assisting patients with first aid when her husband was unavailable. She also read most of his medical texts. Their house was located at 104 S. Jefferson in Mason. Dr. Campbell died in 1891 of typhoid. In the aftermath of that, Gertrude went to medical school at the University of Michigan. She graduated with honors in 1898 after having been one of the first women admitted to the school. She was 30 when she started practicing in Mason.
She met her second husband, the Rev. John O’Sullivan while visiting her brother in North Western Canada, where O’Sullivan was a missionary pastor. They moved to Port Huron in 1914 where John O’Sullivan served as pastor of St. Paul’s Episcopal Church. Gertrude O'Sullivan served as the city physician and was also on the school board. In 1930 John O'Sullivan died and Gertrude took up graduate medical work in Dublin, Ireland and Jersey City, NJ in obstetrics. She returned to Mason where she continued practicing medicine almost up to the day of her death on Sept 14, 1949 at her house at 427 South Jefferson Street.
(The preceding paragraphs are based heavily on the newspaper obituary for Dr. Gertrude O'Sullivan accessed here: https://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=34615629)
There is, as of now, no known record of her interactions with Malcolm.
There are sources that say her house was at 207 Washington Street in Mason, though this was not confirmed with the Ingham County Directory for 1941.