He had been charged with treason for attempting to send a telegram to President Theodore Roosevelt, in which he praised the United States for helping Cuba gain independence from Spain.

One of the consequences of the First Carlist War was the substitution of the Ancien Régime Basque home rule (fueros) by a limited still relevant autonomy.

Arana was born in a jauntxo ("petty noble") family from Abando, a neighbourhood that had been recently incorporated into the city of Bilbao as the new extension for the growth of the industrial era.

Arana attempted to establish a codified orthography[3] and grammar for the Basque language, and proposed several neologisms to replace loanwords of Spanish origin.

Just as others nationalist ideologies were doing during the period, e.g. Spanish nationalism, Arana's historic accounts distorted and magnified events from Basque history.

The PNV, the party in power in the Basque Autonomous Community from the end of Francoism (except during 2009–2012), developed along more nuanced and pragmatic lines in respect of religion and views on race, moving away from his most controversial ideas but not from his political persona.

He was disturbed by the migration into Biscay of many workers from western and central Spain during the Industrial Revolution, into a small territory whose native political institutions had recently been suppressed (1876), believing that their influence would result in the disappearance of the 'pure' Basque race.

Arana and his Basque nationalist movement were persecuted for their ideas against Spanish imperialism, for which he was convicted when he submitted a telegram to Theodore Roosevelt to congratulate him for his assistance in 'liberating' Cuba in 1902, and put to harsh time in prison, which ruined his health and would die soon after.

The nature of this document establishing the Liga de Vascos Españolistas ('League of the Spanish-minded Basques') is still subject to debate as to whether he had sincerely changed his views or whether he was instead merely trying to improve the conditions of his imprisonment.

[8] In February 2017 the People's Party of the Basque Country called for a street named after Arana to be renamed because he “made possible the existence of phenomena such as the ETA terrorist group”.

He believed that the suffix -[n]e was inherently feminine, and new names like Nekane ("pain"+ne, "Dolores") or Garbine ("clean"+ne, "Immaculate [Conception]") are frequent among Basque females.