Langford, Sir Arthur (c.1652–1716), 2nd baronet and MP, was the eldest son of Sir Hercules Langford (1626–1683), 1st baronet, of Kilmackevett, Co. Antrim, and of Summerhill, Co. Meath, and his wife, Mary Langford (née Upton) (1629–c.1692). Sir Hercules, a presbyterian, was sheriff of Co. Antrim in 1661 (though he was removed from the commission of the peace in that county in the aftermath of the plot planned by Thomas Blood (qv) in 1663) and was sheriff of Co. Meath in 1677. He had a house in Belfast, where he was involved in the shipping of beef, and was a burgess of the town from 1669 to 1680. He was made a baronet in 1667. Mary Langford was a daughter of Henry Upton of Co. Antrim and a sister of Arthur Upton (qv).
Arthur entered TCD in 1670 and Lincoln's Inn, London, in 1671. He succeeded his father as 2nd baronet in 1683 and under him, as under his father, Summerhill was a centre of presbyterian worship, with a minister and a meeting-house supported by the family. With Joseph Damer (qv) and others, he was one of the founders of the presbyterian general fund in 1710. He sat in the Irish house of commons, for Duleek, Co. Meath, 1692–3, Coleraine, 1695–9 and 1703–13, and Co. Antrim, 1715 to his death. He was one of a group of MPs who angered the lord lieutenant, Viscount Sidney (qv), after the 1692 session by proposing to take their grievances directly to the government in London.
He died unmarried on 29 March 1716, and was succeeded by his brother Henry Langford (c.1655–c.1725), 3rd baronet, lawyer and politician, who entered the Middle Temple in London in 1677 and was called to the bar there in 1682. He was sheriff of Co. Meath in 1690, a burgess of Trim in 1698, and MP for St Johnstown, Co. Donegal, 1695–9, and was a member of the 1699 commission of inquiry into the Irish forfeitures. With one of his colleagues in the commission, Francis Annesley (qv), he acted as counsel to Bishop William King (qv) in his legal dispute with the Irish Society, and also with Annesley as legal adviser to the bishop on the Act of Resumption (1700).
He purchased an estate at Kings Kerswell, Devon, in 1710 and was sheriff of Devon, 1716–17. He is not known to have married, and died without issue in or by 1725, when the baronetcy became extinct. A younger brother had predeceased Arthur and Henry, while two surviving sisters were among Henry's co-heirs. Through the elder of these, Mary, were descended the Viscounts Langford of Langford Lodge and the Barons Langford of Summerhill.