No record is known of Harris’ education, although his performance in Parliament and his appointment as a recorder suggest a legal training. Under the terms of his father John’s will, of which he was initially appointed executor, he stood to inherit only an unspecified interest in four Cornish manors. However, the premature death of his elder brother Christopher in November 1623 left him as heir to the remaining family estates, which consisted of approximately 1,500 acres, including two manors and two rectories. This legacy was doubly encumbered. His father had died leaving debts of almost £4,790, and had placed both manors in trust for 21 years with a view to clearing this sum.
Unlike his father, Harris enjoyed good relations with Liskeard, the borough closest to Lanrest, his principal Cornish residence. A feoffee of the town lands there by early 1625, he secured one of the borough’s seats in the 1628 general election.
Harris’ apparent interest in Parliament in matters of liberty was reflected at home in his opposition to the Crown’s militia reforms. In October 1629, in his capacity as Cornish provost-marshal, he allegedly joined forces with deputy lieutenants Sir Richard Buller* and Sir Francis Vyvyan* to sabotage the militia’s musters. While antipathy towards Sir Bernard Grenville, an enthusiast for militia reform, may well have influenced Harris’ stance in Cornwall, it should be noted that two months earlier he had also failed to attend musters in Devon. However, the extent to which he might have been associated earlier in the 1620s with leading Cornish opponents of arbitrary government, such as William Coryton*, is difficult to establish.
