Maidstone was first enfranchised as a parliamentary borough, electing two Members of Parliament, in 1552; at the time it was one of the largest English towns not already represented, and was one of a number of boroughs either enfranchised or re-enfranchised during the reign of Edward VI. However, barely had it won the right than its charter was cancelled after the accession of Mary I as a punishment for the town's part in Wyatt's Rebellion. This was the only recorded instance of a borough's right to return MPs being directly revoked until Grampound was disfranchised for corruption in the 1820s (although there were other cases of temporary suspension or of the right lapsing through disuse in medieval times, when representation was less valued).
After the death of Mary I, Maidstone's right were restored, and it elected members to the Parliament of 1560, since when the constituency has been continuously represented. The borough consisted of the whole parish of Maidstone, although the boundaries had no practical effect - the right to vote was vested in the freemen of the town, whether or not they were resident within the borough, provided they were not receiving poor relief. In 1833, just after this franchise was reformed by the Great Reform Act, it was estimated that there were 845 freemen, of whom more than 300 lived over seven miles from the town, and 31 of whom were disqualified from voting because they were in receipt of alms. At the 1831 general election, between 600 and 670 men voted.
A borough of this size was too large to fall under the dominance of a local landowner as was usual in the case of the smaller constituencies in the Unreformed Parliament, and Maidstone remained comparatively free with elections sometimes vigorously contested (and usually expensive for the candidates), although the Finch and Marsham families both had a degree of influence over results in the 18th century. Namier describes in detail the Maidstone election of 1761, showing how at this period the organised divisions among the rank-and-file voters in competitive constituencies tended to be religious rather than party-political; the Whig faction in Maidstone drew its strength from the Nonconformists while the Tories were the Anglican establishment. Yet so complicated was the politics of the period that although the local Whigs had asked Rose Fuller, a personal friend of the Whig Prime MinisterThe Duke of Newcastle, to stand as their candidate Newcastle refused to support him; indeed, Newcastle used his government patronage to force those of the electors employed in the naval dockyard at Chatham to vote for the incumbent Tory MPs, to whom he had already promised his support before Fuller's candidacy was mooted. In the event, though, Fuller succeeded in being elected, many of the government employees defying Newcastle to support him.
At the time of the Reform Act, the population of the borough was 15,387, and it contained 3,018 houses. The boundaries of the borough remained unchanged until 1918. Under the reformed franchise, there were 1,108 electors registered to vote at the general election of 1832. The town continued grow so that by 1865 the electorate had reached 1,817, and this was almost doubled by the extension of the franchise in the second reform act, so that there were 3,420 registered electors for the 1868 general election.
The borough retained two MPs until 1885, when its representation was halved; at the 1885 general election the franchise now extended to 6,530 electors, voting for a population of around 35,000. This was a relatively small electorate for the period and made bribery a practical proposition, and Maidstone was one of a small number of constituencies where corruption was proved after the tightening of election law in the 1880s. Generally a fairly safe Conservative seat, the constituency elected a Liberal candidate against the national tide in 1900, but it was clear that corrupt practices had contributed to his victory and he was unseated on petition; the voters seem to have resented the petition, however, and also elected the Liberal candidate in the ensuing by-election. At the following election in 1906, Maidstone again swung in the opposite direction to the country as a whole, electing a Conservative - one of only five Unionist gains across the country - and the victor was again charged with corruption; on this occasion the candidate was acquitted, but one of the judges noted that "there exists among the voters of this borough a number of the lower class who expect, and are known to respect, a payment or reward for their votes... The proved cases of bribery extend through all the wards."
The borough was abolished with effect from the general election of 1918, but the Maidstone name was transferred to the new county division in which the town stood, which consisted of Maidstone itself and the Maidstone and Hollingbourne rural districts. This contained no towns of any size, but the villages collectively outvoted Maidstone. The new constituency was as safely Conservative as its predecessor, and its boundaries remained unaltered until 1983.
By the 1980s, population growth meant that the constituency was considerably over-sized, with one of the largest electorates in England. In the 1983 boundary revisions, which for the first time reflected the local government boundary changes of the 1970s, the size of the Maidstone constituency was considerably reduced. The area to the north-east of the town, and two wards of the town itself, were moved into the new Mid Kent constituency; as these were strongly Conservative wards and there had been a Liberal surge in the area around the time the Liberal-SDP Alliance was formed, the Alliance had some hopes of making a breakthrough in the revised constituency. However, they could only cut the Tory majority to a little over 7,000 in 1983, John Wells taking over half the votes.
Boundary changes in 1997 saw the constituency abolished and replaced with a new Maidstone and The Weald county constituency. The Maidstone town wards which had been in Mid Kent since 1983 were included in the new seat, and a rural part of the Weald to the south of the town, previously in the Tunbridge Wells constituency was also included; but about a third of the electorate in the Maidstone constituency was transferred to the Faversham and Mid Kent constituency - this included the rural wards to the east of the town, but also the Shepway and Park Wood areas of Maidstone proper.
^At the election of 1702, Marsham and Roberts were returned as elected, and their opponents, Sir Thomas Twisden and Thomas Bliss, petitioned against the result. The Commons on investigation found all four candidates guilty of "bribery and other unlawful practices", declared the election void and resolved that no writ for a new election should be issued until the end of the session
^Dodd was re-elected in 1852 but the election was declared void on petition, and a by-election was held