In the early sixteenth century Stepneth’s father, Thomas, bought property in St. Albans, Hertfordshire, where members of his family held municipal office by the 1480s. Employed as an estate steward by the local priory (1515-28), and later by the Crown,
Stepneth’s proximity to Haverfordwest gave him influence over the borough’s parliamentary seat, and on three successive occasions during the Elizabethan period the town returned him to Westminster. However, in 1589 Haverfordwest was represented by his former enemy Sir John Perrot, Pembrokeshire’s dominant landowner, whom Stepneth now served as an estate steward. He therefore transferred his attentions to Cardigan Boroughs, a seat which was probably provided for him by his then patron, the 2nd earl of Essex. Stepneth is not known to have sought re-election to Parliament until 1604 when, with more than 30 years experience of local office under his belt, he was elected knight of the shire for Pembrokeshire. He was presumably returned on the interest of his second wife’s family, the Philipps’ of Picton, as John Philipps of Picton, his wife’s first cousin, had represented Pembrokeshire in 1601.
Stepneth played only a minor role in all the parliaments of which he was a Member. During the first Jacobean assembly mention of his name is confined to the records of the first two sessions. In view of his former connections with the late earl of Essex, it is not surprising that he was appointed to consider the bill to restore the son of Essex’s executed estate steward, (Sir) Gelly Meyrick† (1 Apr. 1606). Other appointments concerned scandalous ministers (12 June 1604); the subsidy (to which committee he was added on 12 Feb. 1606); the 1604 Welsh Cottons Act (10 Mar. 1606); delays in executions (to which committee he was added on 7 May 1606); and the relief of John Holdich (16 May 1606). On 20 Apr. 1604 he was added to the list of those Members appointed to attend the king at Whitehall that afternoon in connection with the proposed Union.
Stepneth was the subject of parliamentary debate himself in February 1606, when the House learned that he had been summoned to appear in Star Chamber at the instigation of William Warren of Trewern, who controlled three royal corn mills in Haverfordwest as guardian of the daughter of their former lessee, William Morgan.
Stepneth received a grant of arms in March 1606.
