The borough was first represented in the parliament of 1295, and returned two members of parliament (MPs) from 1584 to 1868. At the 1868 election the Second Reform Act reduced its representation to a single seat, and under the Redistribution of Seats Act 1885 the constituency was abolished altogether with effect from the 1885 general election. Newport's re-enfranchisement in 1584, like that of the other Isle of Wight boroughs (Newtown and Yarmouth) seems to have been at the urging of the new Governor of the island, Sir George Carey, a relative of the Queen. In token of thanks, the borough granted him for life the right to nominate one of the two MPs – which seems to have been the reward he expected and the motive for his petition to the Queen in the first place.
Between 1807 and 1811 its two seats were held by two future Prime Ministers: Arthur Wellesley, later to become the Duke of Wellington (who also found himself elected to two other seats at the same time), and Henry Temple (later Lord Palmerston), who would go on to become one of the United Kingdom's most notable Prime Ministers. Palmerston's late father had been unable to convert his Irish title into a United Kingdom peerage, therefore the young politician was able to enter the Commons. The local patron arranging the deal was Sir Leonard Holmes, who made it a condition that they never visited the borough!
The borough was also represented by two other future Prime Ministers in the 1820s. George Canning was MP for Newport when appointed Prime Minister in 1827; however, under the law as it then stood a minister accepting office automatically vacated his seat and had to stand for re-election to the Commons, and Canning chose to stand at Seaford, a government pocket borough in Sussex, rather than fight Newport again. In the by-election that followed at Newport, the vacancy was filled by the election of the Honourable William Lamb, later 2nd Viscount Melbourne, whose father had also represented the borough in the 1790s. However, Lamb remained MP for Newport for only two weeks before also being elected for Bletchingley, which he preferred to represent.
Before the Great Reform Act of 1832, the right to vote was vested in the Mayor and Corporation (consisting of 11 aldermen and 12 burgesses). For much of the previous century the borough was "managed" for the government by the Holmes family, meaning that ministers could generally secure the election of their favoured candidates, but often only at the expense of considerable "gratuities" to the voters – in 1754, this apparently amounted to a payment of £600 for each candidate. The borough consisted of the parish of Newport and of Castle Hold in the parish of St Nicholas, thereby excluding that part of the town which extended over the boundary into Carisbrooke parish; this gave the borough a population of 4,398 in 1831. The 1832 reforms extended the borough to take in the rest of the town, raising the population to 6,700, though the electorate was still only 421.
^Webb was also elected for Ludgershall, which he chose to represent, and did not sit for Newport in this Parliament
^Morgan was also a candidate for Yarmouth, but the election result there was disputed. He sat for Newport until the Yarmouth election was decided in his favour, then chose to represent Yarmouth for the remainder of the Parliament
^March was also elected for Chichester, which he chose to represent, and never sat for Newport
^Jervoise was also elected for Yarmouth, which he chose to represent, and never sat for Newport
^Rushworth was also elected for Yarmouth, which he chose to represent, and never sat for Newport