William Brownlow was born in 1727, in County Armagh, Ireland. He was the eldest son of James Brownlow and was mentioned in his will. William Brownlow, his wife Jane, and their children (Jane, John, and James) immigrated to Charles Town, South Carolina, in December of 1767.
On January 20, 1768, William Brownlow was granted 500 acres in Craven County, South Carolina. The last time he was mentioned in public record was on October 15, 1768, when he purchased 300 acres. He died sometime before January 6, 1773, when his wife is mentioned in a deed as Mrs. Brownlow. She soon after moved to Chatham County, North Carolina, where she married Andrew McBride. He died in 1779 and at some point before February 12, 1800, Jane moved to Orange County, North Carolina. She died sometime after that.