William Pickering was born in Salem, Massachusetts on 11 January 1670/1, the son of John Pickering (1637-1694) and Alice Flint. On 19 June 1695 he married Hannah Browne, with whom he had six children. For much or most of his adult life, Pickering was engaged in the fishing and coasting industries of New England, as shipmaster and trader. A group of his account books (1695-1718), now at the Peabody Essex Museum in Salem, cover voyages of two fishing sloops (Speedwell and Content), as well as the activities of the brig Hope, trading in the fishing settlements of the Newfoundland coast. In the first decade of the eighteenth century, at least, Pickering appears to have made frequent voyages between Massachusetts and Newfoundland, carrying cargo and fishing for cod off the Grand Banks. Petitions survive acknowledging Hope's delivery of critical supplies to the fishing harbor of Ferryland, on Newfoundland, during the harsh winter of 1708-9. Pickering died around 1723, at Salem.

Many of the documents in the collection relate to Pickering's work for Samuel Lillie of Boston. From the 1680s to 1707 Lillie was extensively engaged in commerce between North America, the Caribbean, and Europe. He owned or had interests in at least a dozen vessels; he also fitted out privateers. But Lillie's commercial career ended in ruin. By March 1707 he was unable to meet his obligations, and his ships and real estate were seized. Relatively little is known of the final decades of his life; he appears to have spent much of his time in England, seldom returning to Boston. He died after 1730.