In 1916 the local Parish community saw the need for a Catholic school and started to plan, raise funds and acquire land for this purpose. The foundation stone was laid in 1920 and the building completed in 1921. The Euroa Advertiser dated April 15th, 1921, reported:
"The official blessing and opening of the Convent and School took place on Thursday April 14th, 1921 by His Lordship Bishop McCarthy of Sandhurst and there was a large and enthusiastic gathering representative of all parts of the district and many visitors form further afield. The school was a very fine building and a credit to Father Tobin. The nuns who were coming to Euroa were a distinguished order - The Sisters of Mercy - with very successful teaching records."
Mother Celestine Coyle, Sisters Kieran Fitzgerald, Anthony Callinan and Christina McIntyre arrived from the Convent of Mercy Ascot Vale and formed the first teaching staff. From 1921 pupils were taught up to Grade 8. In 1930 some students remained at St. John's to continue their secondary education. Due to staff shortage some lessons were taught before and after normal school hours and on Saturdays.
From 1950 a series of extensions, renovations and refurbishments have transformed the original St. John's School. These included a new shelter shed, infant room, two classrooms and library (1960's), science room, new toilet facilities, staff, administration and resource room, new classroom (1994), administration block and a multi-purpose building which includes a game/entertainment area, art room, interview room, Reading Recovery room, storeroom and a catering standard kitchen (Mercy Centre 1997).
Most of these developments were through the efforts and finances of the local school and parish communities St John's is proud of its spirit of cooperation and generosity at fundraising and social activities, working bees and supportive committees. Parents designed a garden for the 75th birthday celebration at St John's, (1995), this garden was dedicated to Sister Evarista Dwyer who was in Euroa from 1931 to her death in 24th March 1995, the very weekend of the celebrations. This garden area has twice won a regional prize in the School Garden Competition. Another areas is paved with the names of all the families, staff and Sisters who had been at St. John's until 1995. Work continues on landscaping, grounds improvements and classroom refurbishments and acquisitions of new resources.
From the firm foundation of the Mercy Sisters, the school is now entirely staffed by lay people when the Sisters departed from the St John's at the end of 2002. Their Charism continues on in the school through the vision statements, policy development, school logo (Mercy Cross) and the naming of the Mercy Centre. The school celebrates its foundation on 4th June each year.