The forebears of All Saints College are St John's Boys School, a primary school established in 1838, St Mary's Dominican Convent School, established in 1867, and the Marist Brothers High School, Maitland (later known as St Peter's High School). In September 1990 Bishop Leo Clarke (the Bishop of the Diocese of Maitland Newcastle) announced that the three local
single-sex Catholic high schools would become co-educational, and united under the banner of All Saints College. St Joseph's College, in the rural village of
Lochinvar, and St Peter's were to be Years 7–10 and St Mary's, Years 11–12. The three schools began to operate in their current co-educational format in 1992. The St Mary's and St Peter's campuses are situated in the heart of Maitland and the St Joseph's campus is situated west of Maitland. Following a
Study into the Provision of Catholic Education in the Diocese of Maitland-Newcastle, in 2018
St Joseph's College, Lochinvar terminated its membership of All Saints College and became a stand-alone Years 7–12 school. In 2016, it was announced that St Peter's Campus, Maitland principal Michael Blake had secured the position of principal at Champagnat College, and concluded his role at St Peter's at the end of Term 2. All Saints College is going to convert the school to one campus being St Peters. St Mary's will then be converted into a university. In 2024 it was reported that a teacher at the school was charged with having sex with a 17-year-old student following a police investigation. The teacher was placed on “administrative leave” after being accused of serious misconduct. Police have confirmed the 39-year-old man has been charged with nine counts of sexual intercourse with a person under his care aged between 17 and 18. In 2025, College Principal Brian Lacey officially retired from being Principal at All Saints College, his replacement has been announced as Mr Tony McCudden. ==Notable alumni==