Bradstreet, Dudley (1711–63), spy and fortune-hunter, was born in Co. Tipperary, youngest son of John Bradstreet, a landowner whose family had received considerable Cromwellian land grants. Raised by a foster-family because of his father's high-living, Dudley later attributed his own reckless conduct and morals to being abandoned as a child. Educated in Tipperary town and at a boarding school near Templemore, he detested his teachers but developed a lifelong interest in card-playing. In 1723 he rejoined his family at King St., Dublin, and completed his education at a Latin school in Granard, Co. Longford. After incurring his father's displeasure, he escaped to London with his mistress in 1728, but returned to Ireland to join the army. A trooper in Capt. Welch's regiment of horse at Granard, he married a distant relation, but was disappointed to discover that she had beauty but no fortune. Discharged from the army, he was penniless after the death of his parents, but was awarded a freehold lease worth £36 a year by his brother. His wife died c.1733, but Dudley had already moved on to other pursuits, and divided his time between the gaming table and the bedroom. He had children, but was always reticent about their number and details in his biographical accounts.
In August 1735 or 1736 he captained Westmeath to victory in a football match against Longford, one of the first recorded inter-county games; he was suitably impressed with the intense rivalry, which he claimed exceeded that of hostile armies. Moving to Dublin, he became an attorney's apprentice, but was arrested in 1737 for a debt of £170 after a disagreement between two of his mistresses. To relieve himself from further embarrassments, he married a wealthy widow from Pill Lane after being released on bail. He dabbled in the linen and brewing industries, but he lacked any business acumen and by 1739 he had exhausted his credit. He left Dublin and travelled to England, where he decided to join the army and make his fortune.
Through various illicit schemes, which included gambling, prostitution (for which he was jailed for a fortnight), and selling liquor, he raised £500 in six months. After saving a doctor from blackmail, he was encouraged to become a government spy in 1744. Infiltrating Irish groups to assess the levels of disaffection, he began exaggerating his own importance and inventing stories of various Jacobite plots. In December 1745 he was given a commission as captain and was asked by the duke of Cumberland to attempt to delay Prince Charles and the rebel army at Derby. According to Bradstreet's account, he successfully inveigled his way into the confidences of the Jacobite leaders, using the alias ‘Oliver Williams’, and managed to convince them that any attack would be doomed to failure. When the rebel army decided to return to Scotland, he emerged to claim all the credit, although the significance of his intervention cannot be gauged with any accuracy. On his return to London he found himself denounced by the duke of Newcastle as a papist and criminal. Returning to his get-rich-quick schemes, he invested in the ‘Bradstreet state lottery office’ but only succeeded in losing £20. In 1748 he started touring the countryside claiming to have the power of restoring youth, conversing with the dead, and transporting into small bottles. Having saved £1,500, he lost most of his fortune after a relation cheated him, and he returned to Dublin where he purchased a small brewing company. Once again, he was unable to make a success of a legitimate business, and he was forced to sell everything to pay his creditors. Moving to Multyfarnham, Co. Westmeath, he built a house and a brewery and decided to write his memoirs. After raising finance throughout the country, he published The life and uncommon adventures of Captain Dudley Bradstreet (1755). Its commercial success encouraged him to write a second work, Bradstreet's lives (1757), which has been commended by modern scholars for its sympathetic treatment of female characters. He died in the second week of September 1763 at his home in Multyfarnham. His brother Simon was created a baronet in 1759.