Mary Catherine Aiese was born on December 31, 1947. She formed the group as a high school student in 1962. She led the group throughout its existence, except for 1969–1973 when she stopped performing live, although she continued to record. She married Jonathan O'Leary on 29 Noivember 1969 and took his name. They have two children Nicole and Jonathan Jr and four grandchildren Analiese, Nicholas, Jonathan III and Ava. Mary taught fifth and sixth grade for 32 years. In 1975, she had an unexpected solo hit in the United Kingdom and South Africa with "Shoes". Around this time, she also won a legal dispute with former bandmate Lorraine Mazzola over the right to perform as Reparata. O'Leary reformed the group in 1978 as a part-time project, finally disbanding the group in 2000 when she retired from teaching. She lives in Neponsit, Queens and works as an estate agent and a personal tutor. On 29 November 2019, she and Jon celebrated their golden wedding anniversary.