When William Pearce was born in 1744, in Towson, Baltimore, Maryland, United States, his father, William Pearce, was 32 and his mother, Mary Crawford, was 28. He married Elizabeth Putnam about 1770, in Monkton, Baltimore, Maryland, United States. They were the parents of at least 6 sons and 2 daughters. He died on 18 March 1806, in Baltimore, Maryland, United States, at the age of 62, and was buried in Saint James of My Ladys Manor Cemetery, Monkton, Baltimore, Maryland, United States.