In 1957, Greenhalgh reached the semi-finals of the
Girls Amateur Championship at
North Berwick, losing to
Ruth Porter. In 1959 at Woolaton Park, she reached the final but lost narrowly to
Sheila Vaughan. In 1960 she won the
British Girls' Stroke-play Championship at Ranfurly Castle, an under-21 event, a stroke ahead of the defending champion
Diana Robb. In 1960, Greenhalgh made her debut for England in the
Women's Home Internationals and in 1961 played for Great Britain & Ireland in the
Vagliano Trophy. She missed out on selection for the 1962
Curtis Cup match but later in the year she reached the semi-finals of the
Ladies' British Open Amateur Championship, losing 5 and 4, to
Marley Spearman. In 1963, she played In the
Commonwealth Trophy in Australia. Great Britain won the event with Greenhalgh winning all her six matches. During the trip, she also reached the semi-finals of the
Australian Women's Amateur and won the New Zealand Amateur Championship. In 1966 at Hayling Island, she won the
English Women's Amateur Championship, beating
Jean Holmes, 3 and 1, in the final. She was selected for the
Curtis Cup team for the 1966 match in
Hot Springs, Virginia but later withdrew with an injured wrist, an injury that caused her to miss much of the next two years. Greenhalgh won the
Ladies' British Open Amateur Stroke Play Championship two years in succession, in 1974 and 1975, and won the
Welsh Women's Open Stroke Play Championship in 1977. In 1977, she led the qualifying for the
Ladies' British Open Amateur Championship while in 1978 she reached the final, losing by one hole to
Edwina Kennedy. In 1979, she won the
English Women's Amateur Championship for a second time, beating
Sue Hedges in the final. Her wrist injury recurred in mid-1979 and marked an end to her appearances at the highest level. Greenhalgh was a regular player in international matches for Great Britain & Ireland and for England in the 1970s. Over her career, she played in five
Curtis Cup matches, three times in America, and four
Vagliano Trophy matches. As well as her
Commonwealth Trophy match in Australia in 1963, she also played in 1975. She played in the
Espirito Santo Trophy in Spain in 1970, in the Dominican Republic in 1974 and in Fiji in 1978. ==Personal life==