Member of Parliament
At the 1661 English general election Harbord was returned as the Member of Parliament for Launceston and aligned with the faction of Edward Hyde. In the Commons, Harbord was one of the most active members of the Parliament; he was appointed to 694 committees and delivered 65 reports, 15 of them from grand committee. He acted as teller in five divisions and as messenger from the Commons on 12 occasions, and made 123 recorded speeches. He served as chairman of the revenue committee, from which he presented 12 reports. In 1662 he was appointed to the council of Catherine of Braganza.
In 1664, Harbord was listed as a member of the court faction and he was named to the committee to consider the Conventicle Act 1664. His extensive parliamentary activities also included opposition to a bill to prohibit the import of Irish cattle and supporting an inquiry into the Great Fire of London so vigorously that he was the first MP named to the committee. He was also among the members appointed to receive information about the "insolence of Popish priests".
Despite his earlier politics, Harbord welcomed the dismissal of the Earl of Clarendon in 1667 after the disastrous Second Anglo-Dutch War. When parliament met during the Third Anglo-Dutch War, Harbord welcomed the proposal for a naturalization bill, only regretting that it would be restricted to Protestants. He opposed the Declaration of Indulgence (1672) on the basis that statute law should be made only by Parliament, but he was conciliatory towards nonconformists. Harbord was a member of a committee opposing the marriage of James, Duke of York to Mary of Modena in 1673. In parliamentary debates over the Cabal ministry in 1674, Harbord spoke in opposition to the political activity of George Villiers, 2nd Duke of Buckingham.
By 1677, Harbord was recorded on the lists of Anthony Ashley-Cooper, 3rd Earl of Shaftesbury as "doubly vile" owing to his support for the succession of the Duke of the York. In 1678 Harbord was reckoned as being a government speaker and a court supporter. Having become rich through his various crown offices, he was accused by Henry Goring of benefiting from the sale of crown lands. Harbord replied that he had actually saved the crown considerable sums of money: "The King has granted me four manors of £400 p.a. each, not a farthing profit to me as long as the queen lives. As I have saved the crown £80,000 at a time, I desired only a mark of my service, and that is all."
Although he declared that "I have always been for the Church of England, and I will die in it", he supported a bill from the Lords to relax the Test Act 1673. He served on the committee of inquiry into the Popish Plot. He helped to consider the bill to hinder Roman Catholics from sitting in Parliament, but warmly supported the Lords amendment to except the Duke of York. By this stage, Harbord was widely respected in the Commons for his knowledge of parliamentary procedure, and towards the end of the Cavalier Parliament he was included in the committee to devise means of surmounting the royal veto on the 1678 militia bill.
In 1679, he was elected to the Habeas Corpus Parliament where he continued to be recorded as "vile" on Shaftesbury's list. Harbord was named to six committees and made two recorded speeches. On 22 March 1679 he openly criticised the pardon given to Lord Danby by Charles II, stating: "Did the King ever pardon anyone after an impeachment was against them? This way of pardoning, an impeachment depending, is one of the most dangerous consequence in the world, both to King and people." He was absent from the Commons during the vote on the Exclusion Bill on 15 May and died shortly afterwards, on 25 May 1679.
Despite his role in parliamentary affairs as an indefatigable legislator, Harbord was a controversial figure in his own lifetime owing to the large amounts of money he made through his official roles. He was described by the contemporary historian, Gilbert Burnet, as "very rich and very covetous". His reputation was handled very severely in a 1677 pamphlet entitled 'A List of the principal Labourers in the great Design of Popery and Arbitrary Government'.
