During the general elections of September 1780, Pitt contested the
University of Cambridge seat, but lost. Still intent to enter Parliament, Pitt, with the help of his university comrade,
Charles Manners, 4th Duke of Rutland, secured the patronage of
James Lowther. Lowther effectively controlled the
pocket borough of
Appleby; a by-election in that constituency sent Pitt to the
House of Commons in January 1781. Pitt's entry into parliament is somewhat ironic; Pitt later rallied against the very same rotten boroughs that gained him his seat.
In Parliament, the youthful Pitt cast aside the withdrawn and aloof nature that characterised him during his university days, emerging as a noted parliamentarian and debater. Pitt originally aligned himself with prominent
Whigs such as
Charles James Fox. With the Whigs, Pitt denounced the continuation of the
American War of Independence. Instead he proposed that the Prime Minister,
Lord North, make peace with the rebellious American colonies. Pitt also supported parliamentary reform measures, including a proposal that would have checked electoral corruption. He renewed his friendship with
William Wilberforce, with whom he frequently met in the gallery of the House of Commons, and they formed a lasting friendship.
After Lord North's ministry collapsed in 1782, the Whig
Charles Watson-Wentworth, 2nd Marquess of Rockingham was appointed Prime Minister. Pitt was offered the minor post of Vice-Treasurer of Ireland; but he refused, considering the post too subordinate. Lord Rockingham died only three months after coming to power; he was succeeded by another Whig,
William Petty, 2nd Earl of Shelburne. Many Whigs who had formed a part of the Rockingham ministry, including
Charles James Fox, now refused to serve under the new Prime Minister. Pitt, however, was comfortable joining the Shelburne Government; he was appointed
Chancellor of the Exchequer.
Fox, who became Pitt's lifelong political rival, then joined a coalition with Lord North, with whom he collaborated to bring about the defeat of the Shelburne administration. When Lord Shelburne resigned in 1783,
King George III, who despised Fox, offered to appoint Pitt to the office of Prime Minister. But Pitt wisely declined, for he knew he would be incapable of securing the support of the House of Commons. The
Fox-North Coalition rose to power in a Government nominally headed by
William Cavendish-Bentinck, 3rd Duke of Portland.
Pitt, who had been stripped of his post as Chancellor of the Exchequer, joined the Opposition. He raised the issue of parliamentary reform in order to strain the uneasy Fox-North Coalition, which included both supporters and detractors of reform. He did not advocate an expansion of the electoral franchise, but he did seek to address bribery and
rotten boroughs. Though his proposal failed, many reformers in Parliament came to regard him as their leader, instead of Charles James Fox.
So as to reduce the power of the Opposition, Pitt offered Charles James Fox and his allies posts in the Cabinet; Pitt's refusal to include Lord North, however, thwarted his efforts. The new Government was immediately on the defensive, and was defeated on a
Motion of No Confidence in January 1784. Pitt, however, took the unprecedented step of refusing to resign despite such a defeat. He retained the support of the King, who could not tolerate the Fox-North Coalition. He also received the support of the
House of Lords, which passed supportive motions, as well as much support from the country at large, in the form of many petitions approving of his appointment (which influenced some local MPs to switch their support to Pitt) and he was accorded the Freedom of the
City of London. Whilst returning from this ceremony the attendees chose to pull Pitt's coach home themselves as a sign of respect. When passing the Whig club the coach came under attack from a group of men who tried to assault Pitt. When news of this spread it was assumed that Fox and his associates had tried to bring down Pitt by any means. Pitt gained great popularity with the public at large as "Honest Billy" who was seen as a refreshing change from the dishonesty, corruption and lack of principles widely associated with both Fox and North.
Despite a series of defeats in the House of Commons, Pitt defiantly remained in office, watching the Coalition's majority shrink as some Members of Parliament left the Opposition to join his side. The defectors, however, were not sufficiently numerous to give Pitt a majority. In March 1784, Parliament was dissolved, and a
general election ensued. An electoral defeat for the Government was out of the question, for Pitt enjoyed the support of King George III. The aid of
patronage and bribes paid by the Treasury were normally expected to be enough to secure the Government a comfortable majority in the House of Commons but on this occasion the government reaped much popular support as well. In most popular constituencies the election was fought between clear candidates representing Pitt or Fox/North. Early returns showed a massive swing to Pitt, with the result that many opposing MPs either defected, stood down or made deals with their opponents to avoid expensive defeats. A notable exception came in Fox's own constituency of
Westminster, which had one of the largest electorates in the country. In a contest estimated to have cost a quarter of the total spending in the entire country, Fox bitterly fought against two Pittite candidates to secure one of the two seats for the constituency, with every possible campaigning method tried. When polling finished massive legal wranglings ensued, involving the examination of every single vote cast, which dragged on for more than a year. In the meantime Fox sat for the pocket borough of
Orkney but many saw the dragging out of the result as excessive vindictiveness on the part of Pitt and eventually the examinations were abandoned, with Fox declared elected. Elsewhere Pitt won a massive personal triumph when he was successfully elected a
Member of Parliament for the University of Cambridge, a constituency he had long coveted and which he would continue to represent for the remainder of his life.