Sweetman (Irish: Suatman or Swetman) is an Irish surname derived from the Old English bynames of Swet, Sweta and Swete which are derived from the word 'Swete' (meaning 'popular') and survived into the medieval period, being later Gaelicised to 'Suatman'.
The first Sweetmans in Ireland became known as Old English, English settlers who moved to Ireland following the Norman invasion of Ireland in 1169. They lived in the south-east counties of Wexford and Kilkenny.
The Sweetmans or Swetmans succeeded the D'Erleys in their property of Earlstown, and title Baron of Erley, probably towards the close of the 14th century, when the family first began to take a prominent place in local affairs. Milo Sweetman was treasurer of the Diocese of Ossory in 1360, in which year he was elected Bishop of Ossory by the Chapter. His election was cancelled by the Pope, who, however, in the following year appointed him Archbishop of Armagh Having governed the Primatial See for nineteen years he died in 1380, and is buried in Dromiskin, County Louth.
John Sweetman was appointed Keeper of the Peace for Co.Kilkenny, in 1382; he was Sheriff of the same county 13 November 1390. In 1405, Nicholas Sweetman was appointed Keeper of the Peace for County Kilkenny. In 1478, John Sweetman was chief lord of all the Barony of Erley (source: Register of Kells Priory). He is, no doubt, identical with the "John Sweetman, son and heir of Nicholas Sweetman of Castellyse (i.e. Castellyfe, or Castle Eve) in the Co. Kilkenny, gent.," who received a royal pardon for treasons &c., 23 October 1482 (source: Patent Rolls).
William Swetman, Baron of Erley, died, as his monument in Newtown Church testifies, in 1507.
James Swetman was presented, with the other gentry of Co. Kilkenny, in 1537, for charging coyne and livery. He was High Sheriff of County Kilkenny in 1543. He was still living in March, 1549, when we find James Sweteman, of Castelliff, and William Swetman, of Tullahaght, County Kilkenny, gents., receiving pardons.