Emery’s career in the law began in the 1380s with him building up a practice as an attorney in the court of common pleas, notably in the business of registering conveyances of landed property in Kent. He was already well acquainted with William Makenade, a fellow lawyer who a few years later was to achieve local prominence as the archbishop of Canterbury’s steward, and it may be that Makenade assisted in his training. He also had contact with two future judges, both with Kentish connexions: William Rickhill and William Brenchesle. In 1384 Emery was made a trustee for the sale to Makenade of the reversion of the manor of Horton by Roger, de jure Lord Northwood, and arrangements for the further settlement of this property were still requiring his attention 25 years afterwards.
Emery’s involvement in the affairs of Canterbury had begun by 1396, when he received from the city’s coffers the sum of 13s.4d., in order to pay another lawyer engaged to appear on the community’s behalf at the assizes; and he was elected bailiff for the first of four terms in 1404. No doubt his counsel was often given to the civic authorities, although there is no record of his ever receiving a fee on a regular basis. In November 1409 he and four others obtained a royal licence to grant a messuage in Canterbury to the commonalty as an endowment for works on the city walls and fortifications. Perhaps this was the same building as Le Lyon which he and others formally conveyed to the bailiffs and citizens two years later, for eventual use as an extension to the guildhall. Emery was present at the parliamentary elections held at Canterbury in 1411, then attesting the composite indenture for the shire and both its boroughs. When returned to Parliament for apparently the only time, at the beginning of Henry V’s reign, he was serving as one of the city’s 12 jurats.
The fruits of Emery’s professional career enabled him to become established as a landowner. He is recorded from 1382 onwards making purchases of parcels of land and other properties scattered throughout east Kent, but concentrated in the main on Harrietshaw and Canterbury. According to the assessments made in 1412 for the purposes of taxation, his landed holdings then provided him with an annual income of £20 6s.8d.
Emery was still active, as a feoffee of lands to the south of Canterbury, in 1427. In his will, made on 11 Mar. 1431, he required his executors to settle on his widow his house in Stour Street, Canterbury, and to ensure that she received not only the £20 she had brought him as a marriage portion, but also another £20 from his estate, together with all her own household stuff and half the contents of their home. He died at an unknown date sometime after Michaelmas 1431 and before 26 Aug. 1432, when the will was enrolled in the burghmote court of the city.