The Archdiocese of Delhi was once part of the Archdiocese of Agra. It was in the year 1910, by a Decree of the Sacred Congregation of Faith, that Simla Archdiocese was erected. The Holy See entrusted this Archdiocese to the English Capuchins and chose Fr. Anselm Kenealy, a member of the English Capuchin Province, to be the first Archbishop. He was consecrated on December 21, 1910. Archbishop Sylvester Patrick Mulligan succeeded him in 1937 and in that year, the city of Delhi and those portions of the Punjab which were under the Archdiocese of Agra were added to the Archdiocese of Simla. With this addition, the Archdiocese was renamed as: Archdiocese of Delhi-Simla and Archbishop Mulligan became the first Archbishop of the Archdiocese of Delhi-Simla. On 8th December 1945, Sacred Heart Church in New Delhi was consecrated by Archbishop Mulligan and declared his Cathedral.

Archbishop Mulligan passed away in 1950. In the following year, Rt. Rev. Joseph Fernandes, the then Auxiliary Bishop of Calcutta, took over as the first Indian Archbishop of Delhi-Simla.

The history proper of the Archdiocese of Delhi begins on June 4, 1959 when the Archdiocese of Delhi -Simla was bifurcated into two separate ecclesiastical units, viz., Diocese of Simla-Chandigarh and Archdiocese of Delhi and both were handed over to the Diocesan clergy. While Archbishop Joseph Fernandes was re-named the Archbishop of Delhi, Msgr. John Burke, the then Vicar General of Delhi, was consecrated on November 1, 1959, as the first Bishop of the newly carved out Diocese of Simla-Chandigarh. On the same day, Fr. Angelo Fernandes, the then Administrator of Holy Name Cathedral, Bombay, was consecrated as the Co-adjutor Archbishop of Delhi.

At the time of the bifurcation, in 1959, the Archdiocese of Delhi had only 10 churches. In spite of these limitations, a planned growth for the Archdiocese was envisaged by the then Archbishop Joseph Fernandes and his Co-adjutor Archbishop Angelo Femandes who succeeded him in 1967. Most Rev. Angelo Fernandes retired as Archbishop of Delhi in 1990 and Most Rev. Alan Basil de Lastic took over as the new Archbishop on January 27, 1991. To assist the new Archbishop, Rt Rev. Vincent M Concessao was consecrated as the Auxiliary Bishop on April 1, 1995, who later was appointed as the Archbishop of Agra. Archbishop Angelo Fernandes passed away on January 30th 2000 and in the same year Archbishop Alan de Lastic too died in a tragic accident at Poland on 21st June. After the death of Archbishop Alan, Archbishop Vincent Concessao was installed as the fourth Archbishop of the Archdiocese of Delhi on 19th November, 2000. On 11 March, 2001, Rt. Rev. Anil J.T. Couto was consecrated as the Auxiliary Bishop of Delhi. In March 2007 Bishop Anil was appointed as the Bishop of Jalandhar. On 21st February, 2009 Rt. Rev. Franco Mulakkal, a priest from the diocese of Jalandhar was consecrated as the Auxiliary Bishop of Delhi. In April 2009 another priest of the Archdiocese Rt. Rev. Ignatius Mascarenhas was consecrated the Bishop of Simla-Chandigarh Diocese.

The Holy Father, Pope John Paul II, visited the Archdiocese in January 1986 and he re-dedicated it to the Sacred Heart of Jesus and commended to the Lord all the people entrusted to the care of the Archdiocese. In November 1999 Holy Father, Pope John Paul II visited Delhi again to release his Encyclical Ecclesia in Asia (Church in Asia). He did so in the Sacred Heart Cathedral in the presence of many bishops of Asia and various other priests and lay people.

At present the Archdiocese of Delhi comprises the Union Territory of Delhi and the districts of Gurgaon, Rohtak, Mahendragarh, Sonepat, Faridabad, Mewat, Jhajjar and Rewari of Haryana.