[1] He served as a Member of the Cavalier Parliament (1661–1679), though he was relatively inactive and participated in only 35 parliamentary committees.
On 21 December 1666, Lucy presented the estate bill of Henry Mildmay to the House of Lords.
In the autumn of 1667, he was appointed to committees tasked with examining shortcomings in the act restricting the import of Irish cattle and reviewing an additional bill on the matter.
Lucy also participated in committees focused on improving observance of the Lord's Day (1671) and on measures to prevent abuses in parliamentary elections (1673).
However, Sir Joseph Williamson, an influential official, soon described Lucy as “very bitter against the lord treasurer.” He was subsequently managed by his partners in the Weaver Canal project, including the Lord Gerard of Brandon and Gilbert Gerard II.