John had set up in business as a draper in Salisbury before November 1375, when Roger Wallop of Andover, Hampshire—presumably a kinsman of his—assigned to him a reversionary interest in a messuage in the city. In 1377 he was appointed one of the many executors of William Teynterer, junior, a prominent citizen of Salisbury. Then, in 1384, he went surety for the attendance of both John Salisbury (Member-elect for Salisbury) and John Avery I (representative for Old Sarum) at the second Parliament of that year. In 1385 he did the same on behalf of David White, and the following year he went bail for Adam Dunmere, a local man who was being sued for debt.
Wallop died early in 1405. His will is no longer extant, but it is known from other sources that he bequeathed property to the city of Salisbury, and that his executors included Thomas Mason and William Boyton.