His birth is often given as 12 Aug 1603 in Bradwell, Suffolk. Great Migration just estimates 1603, and says that there are no records of a William Ballard in Bradwell. The origin probably comes from a 1638 list of those in Suffolk, England, who were delinquent in their payments of ship money includes a few names that are annotated as having gone to New England; as published, these entries include William Ballard of Bradwell [NEHGR 61:69]. However, William Bullard of Dedham also fits with the timing for a daughter Mary recorded in that register in 1630.

Her name is always given as Lee, but Great Migration found no evidence for it.