Porter and Thomas Lavyngton dominated the parliamentary representation of Reading in the first half of the 15th century, sitting ten and 12 times respectively during that period, a record unmatched by any other burgess. Little is known about Porter’s family or antecedents; although he was almost certainly locally born, and quite likely the son of John Kent, a prominent townsman, after whose death in 1413 he took over his fish stall in the market. Porter is described as a mercer on the parliamentary return of February 1449, but he probably also had other commercial interests, for he continued to rent this stall until 1454.
In addition to his service in the Commons, Porter was closely connected with the administration of the borough for nearly 40 years. After attending the election of MPs in 1420, he witnessed the returns of 1426, 1429, 1431, 1442 and 1453—on almost all occasions, in fact, when he was not himself elected. First appointed mayor in 1427, he probably became coroner for Berkshire at about the same time. He was replaced in this office in July 1430, on the ground that he was busy elsewhere, and, indeed, he was then mayor again. During his second term of office, the corporation voted him and his successors five marks a year for the maintenance of their ‘status’. In 1431, Porter was entrusted with the safe-keeping of £20 belonging to the community, and in the following year he was elected one of the 24 burgesses to negotiate with the abbot of Reading on behalf of the guild merchant. Henceforth he was frequently employed on the town’s behalf in lengthy lawsuits connected in the main with the dispute between the abbot and the burgesses over guild rights: in 1433-4 he and Robert Morys received 40s. as expenses for a visit to London ‘pro certis causis maioris et communitatis’ and 14s. for riding to Newbury. In 1434 he was important enough to be listed among the Berkshire gentry and notables who were to take the oath not to maintain breakers of the peace.
Porter was nominated mayor in 1439, but on this occasion he was not accepted by the abbot for the office. During his third mayoralty, in 1441-2, he was elected to head a commission to supervise the repair of the guildhall, and to tax the guild members accordingly. Four years later he was again chosen for the mayoralty, but once more the abbot objected. At the close of the decade, he sat in three successive Parliaments, those of 1447 and of February and November 1449; and for his expenses in attending the second, which met at Winchester for its final session, the authorities granted him ten marks.
Porter probably died shortly after 1454, when his name last occurs in the town records. In 1452 he had made over all his goods and chattels to Sir John Lisle, Thomas Beke of Reading and others, perhaps to avoid their forfeiture in a lawsuit. Robert Kent, whose entry into the guild Simon had sponsored five years earlier, may well have been his son. Another presumed son was John Kent, who entered Winchester college in 1431, and died there, while still a scholar, in 1434.