Sydnor was a merchant and slave trader. He was born in Virginia in 1812 and came to Texas in 1838 on an inspection tour, then moving his family to Galveston in 1840. He started a commission and real estate company, J. S. Sydnor & Company. He also served as an alderman and mayor of Galveston and built a sprawling house, known as the Powhatan House. His business expanded to include slave sales and auctions at his place of business on the Strand. He served briefly in the Confederate Army and moved to New York after the Civil War to open a brokerage there. He died in 1869 while visiting his brother in Lynchburg.
