He studied at the seminaries of Esztergom and Budapest, and the Pontifical Lateran University in Rome (where he attained doctorates in both theology and canon law).

For the next eight years, he taught as a professor of theology and canon law at the Seminary of Esztergom, and held guest lectures at several foreign universities.

[4] He received his episcopal consecration on 6 January 2000 from Pope John Paul II with Archbishops Giovanni Battista Re and Marcello Zago, OMI, acting as co-consecrators.

[12] In 2015, Erdő's second address to the synod was described by journalists, such as Damian Thompson of The Spectator and John L. Allen Jr. of the Boston Globe, as more theologically conservative in its tone.

[16] Erdő requested that the Hungarian Chief Prosecutor's Office legally, morally, and politically rehabilitate Cardinal József Mindszenty, his predecessor, who fought Hungary's Communist regime and was arrested by the country's Stalinist dictatorship, after which he sought refuge in the American embassy in Budapest.

[18] During a Vatican press conference in October 2014, Erdő expressed opposition to the idea of allowing divorced and remarried Catholics to receive Holy Communion.

[20][21] Erdő has written about the special socio-economic conditions of the Romani people and has openly wondered on the correct way to evangelize them.

[22] Erdő has focused on Hungary's need to restore its faith and hope, while celebrating Midnight Mass at St. Stephen's Basilica in Budapest, to mark the Christmas holiday.