At Lingfield, Wool Winder emulated his dam by winning the £1,675 Lingfield Park Plate by beating the 1906 St. Leger winner Troutbeck, followed closely by a win in the Sussex Stakes. On 15 August, he won the City of London's Breeders' Foal Stakes, for which St. Windeline walked-over in 1902, at 100 to 15 odds. On 11 September, Wool Winder won the St. Leger Stakes. He was the betting favourite at 11 to 10 and was uncontested for most of the running, crossing the finish by six lengths over Baltinglass, Acclaim and Larig. Wool Winder ran eight times in 1907 and won £10,556 for Baird. Heralded as a top prospect for the coming season, Wool Winder was unplaced to the colt Succor in his first outing at the Newmarket March Stakes. Baird attributed the loss to the high weight Wool Winder carried in the running, more than Succor. Approached by representatives of the Hungarian government stud in March, Baird refused to sell Wool Winder for £32,000. Wool Winder's form suffered late in the season, and his training was stopped for most of the season in the hopes his health and condition would improve for the Ascot Gold Cup. He was ultimately withdrawn from all of his engagements for the entire racing season due to health and soundness issues, his unsuccessful run in the March Stakes his only outing for the year. In November, Baird offered to sell Wool Winder to the Hungarian government for £25,000, but the offer was refused. In April at Newmarket, Wool Winder lost by a head to Lafayette in the one and a quarter-mile March Stakes. He finished sixth and last in the Coronation Cup won by J. B. Joel colt Dean Swift, dropping sharply out of the running shortly after the start. Wool Winder was retired from racing in July 1909 and was sold to the Austrian government stud for an estimated 15,000 guineas (500,000 crowns). Wool Winder stood at Aristides Baltazzi's Napajedla Stud in Austria-Hungary (now Czech Republic) alongside Matchbox and Wombwell. Wool Winder was the leading sire in Austria in 1916 and 1928. He died on 28 November 1928 at 24 years at the Kottingbrunn Stud after contracting an intestinal infection. Considered a success during his lifetime, few of his sons became breeding stallions and his sire line is not prominent in modern times.