Bishop Percival Fernandez was ordained a Priest for the Archdiocese of Bombay on December 21, 1960 at St. Pius X College, Goregaon, by His Eminence Valerian Cardinal Gracias. Was ordained a Bishop on April 21, 2001 at the Don Bosco Grounds, Matunga, Mumbai , by Ivan Cardinal Dias.

From the year 1961 to 1974 he functioned as Assistant in the Parishes of St. Stephen's, Cumballa Hill; St. Ignatius, Jacob Circle; St. Michael's, Mahim; and Holy Name Cathedral, Wodehouse. During this period he also functioned as the Principal of St. Stephen's School, from 1961 to 1965; and St. Ignatius High School,from 1967 to 1971.

In 1974, he was appointed Parish Priest of St. Ignatius Church, Jacob Circle, Bombay. In 1978 he was deputed by Cardinal Gracias to go to Bangalore and help in the Administration of St. John's Medical College, a CBCI Institution.

From 1978 to 1980, he was the Administrative Officer of St. John's Medical College in Bangalore.

In 1980, Fr.Percy, who holds an M.A. in History through the Pune University, was deputed by the Catholic Bishops of India, who own St. John's Medical College, to do Post Graduate Health Management Studies in the U.S.A.

He did his Master's in Business and Public Administration, with Health and Major, and secured a PhD in Health Management in the U.S.A. and returned to St. John's Medical College, where he took over as Director and Chief Executive of St. John's National Academy of Health Sciences in the year 1985.

He worked in this capacity till the end of August, 2000, and after having served a total of 22 years at St. John's, retired from St. John's and returned to Mumbai as Professor at St. Pius X College, on September 01, 2000.

On March 13, he was appointed Auxiliary Bishop of Bombay by His Holiness Pope John Paul II, and was ordained a Bishop by His Eminence Ivan Cardinal Dias on April 21, 2001. He continued to lecture on Pastoral Management at the Bombay Seminary at Goregaon. Was on the Faculty of St. John's National Academy of Health Sciences in Bangalore, and at J.D.V., Papal Seminary, Pune till 2012. In 2002 he was elected Secretary General of the Catholic Bishops' Conference of India for a period of 4 years. He retired as Auxiliary Bishop of Bombay on December 20, 2010, but continues to conduct Seminars for Priests and Religious Teachers on 'Leadership and Pastoral Management' in different Dioceses all over the country and abroad. In addition he has been placed in charge to raise a HEALTH CORPUS FUND to assist poor Catholic families in their health care needs. Started in the year 2006, the Fund has already nearing 13 crore mark, and has assisted over 1,020 needy Catholic Families in this Archdiocese to meet their Hospital Bills.