In 1971 Hayes won the Spanish Open at the age of 18 years and 290 days, becoming the youngest winner on the European Tour, a record which stood until Danny Lee won the 2009 Johnnie Walker Classic. By 1973 he was fourth on the European Tour Order
of Merit, improving to second in 1974 and first in 1975. He also finished in the top four in 1978 and 1979, but played little professional golf after his late twenties.
Since he stopped playing tour golf Hayes has remained involved in the sport in a variety of ways. he was worked as a broadcaster in South Africa and for the Golf Channel, started and edited a golf magazine and helped to found an internet golf shopping business. He is involved in golf course design through a company called Matkovich & Hayes, although he deals only with marketing and public relations, while the actual design is handled by his business partner Peter Matkovic, a professional golfer with a modest playing record. Hayes also works as a public speaker and gives golf clinics.