He is known for his outspoken anti-ETA rhetoric[2] and social ultracatholicism[3] Mayor Oreja was born and raised in San Sebastián, in the Spanish Basque Country, where he attended a school run by Marianists.

In 1989, at the request of Manuel Fraga, Mayor Oreja returned to politics to help the newly founded People's Party (PP).

He famously coined the term "tregua-trampa", or "trap truce", and he publicly stated his refusal to engage in any political negotiation with ETA.

[6] His tenure as Minister of the Interior marked Mayor Oreja's height of influence, and thereafter his political career experienced an irregular decline.

In 2001, his party chose him as candidate to the Basque regional presidency in that year's election, so he resigned as Minister of the Interior to focus on running the campaign.

[9] Although his ticket never polled high enough to secure a plurality of seats in the Basque parliament, Mayor Oreja and the Spanish Socialist Party made it clear that were the incumbent lehendakari Juan José Ibarretxe to fail to secure an absolute majority in the Basque parliament, Mayor Oreja would form a minority government instead with the Socialist's support.

[11] In 2004 he was mentioned as a potential successor to the outgoing Spanish prime minister José María Aznar,[12] but the latter finally opted for Mariano Rajoy instead.

[23] He has denounced what he deems as the moral decadence of modern society,[24] and claimed that abortion is something "worthy of bolcheviques",[25] and deployed intense lobbying activity defending these stances in Latin America.