In 1952 the southern region of Diocese of Mylapore was separated to form a new Diocese. On 25th of March 1953, His Excellency Most Rev. Arokiasamy Sundaram became the first Bishop of the newly found Diocese of Thanjavur. Rupees Twenty Thousand was donated by the Bishop to the school. Along with an aid from the Govt. Three class rooms were built with necessary facilities. In June 1958 Rev. Fr. S. T. Amalanathar became the AHM. In June 1960 Rev. Fr. Packiasamy taught here. In 1960 Rev. Fr. S. T. Amalanather went to America to pursue higher studies. Rev. Fr. Packiasamy was transferred to St. Antony's High School in Nagappattinam as HM.

After Rev. Fr. Victor Fernandez Retired, Rev. Fr. Gnaninathar from the Dioceses of Kumbakonam was the HM here for two and a half years. De Britto Hall was inaugurated with five class rooms by the Bishop during this period.

After returning from America, Rev. Fr. S. T. Amalanathar served as the HM from 1964 to 1981. To provide educatioan to the poor of the neighbouring villages and to improve their talents in sports, he started a hostel in the campus. Rev. Fr. H. Amalraj who was the AHM, was promoted as HM and sent to St. Arulanandar High school, Pallankovil.

Rev.Fr. Raphael was here for a year in 1967 and was sent as HM to Arockia Annai High School at Punalvasal. Rev. V. Savarimuthu served this school from 1971 to 1976.

Rev. Fr. Amalanathar faced several hardships during his tenure to develop this Institution. He built a section with four class rooms and initiated the construction of the first floor above the 'U' shaped building. At this time, Rev. Fr. Amalanather was appointed the Bishop of Tuticorin.

From 1981 to 1986 Rev. Fr. S. Packiasamy was the HM and he constructed three rooms from Science Laboratory, seven class rooms, School Office and Head Master's Office. They were blessed by the Bishop of Thanjavur. The rooms on the western side were made into halls.

The old Don Bosco Hall was demolished and class rooms were constructed to mark the Centenary of St. Antony's High School. Rev. Fr. Pakiaraj Royan SDB was the AHM from 1981-83. He was promoted as the HM to the Don Bosco Matriculation School at Thanjavur in 1983. Rev. Fr. Savariraj was teaching here from 1982-85.

Several illustrations students have gone out of this glorious institution. The school has its motto, "EXCELSIOR". It has produced several Bishops. They are H.E. Most Rev. Arockiasamy Sundaram Bishop of Thanjavur. Auxillary Bishop of Diocese of Mylapore, H. E. Most Rev. Carvalho, Bishop of Kumbakonam H. E. Most Rev. Maria Selvam Bishop of Vellore. H. E. Most. Rev. David Maria Nayagam, H. E.Most. Rev. B.C.Balasamy Bishop of Nellore and H.E. Most. Rev. M.Devadoss Amburose, Bishop of Thanjavur. Several dignotive in politics, Government Administrative Department and Businessman have emerged from this institution.

The school has achieved academic excellence securing above 90% in SSLC Exams.