[4] He married his cousin from the Durango-based Maguna family; its representatives commanded tercios in Flanders, one was the founder of Montevideo[5] and another served as governor of Buenos Aires.

María de la Soledad married a Carlist politician, deputy mayor of Bilbao and senator Manuel Lezama Leguizamón.

[26] However, later on the family moved towards more moderate, fuerista positions; disappointed by the curtailment of Biscay autonomous establishments in the 1840s, they were involved in conspiracy against centralizing policy of Espartero.

In 1864 he was appointed to the Biscay diputación foral as regidor electo from the so-called Bando Gamboino, a historical-geographical unit that the county of Durango formed part of;[29] as such he entered Gobierno del señorio de Vizcaya, a provincial self-government.

[34] In hope to get the traditional fueros, abolished during the Isabelline period, reinstated,[35] in May 1874 the Junta adopted an openly rebellious stand and offered its support to the Carlist claimant, Carlos VII.

[37] He also engaged personally and offered the claimant hospitality at the family estate; the proposal was accepted and Ampuero actually hosted the Carlist king in Durango during an unspecified period.

[38] However, at least theoretically, Ampuero was still forming part of the Biscay diputación foral; he was listed as its diputado by the Madrid Guía oficial de España for the years of 1875[39] and 1876.

He did not abandon his earlier declaration and in the late 1870s allegedly he remained faithful to the claimant; however, as the movement was in total disarray and there was hardly any Carlist organization operational in Vascongadas,[41] his loyalty to Carlos VII did not translate to any action.

This changed in 1880, when Ampuero decided to stand as a candidate for the Biscay diputación from Durango; thanks to the position of his family, but also thanks to Traditionalist strength in the county, he was elected[42] and unsuccessfully coveted the post of the president.

As the Carlists officially did not field party candidates, during the 1881 electoral campaign for the lower chamber of the parliament he competed as an individual in Durango and emerged victorious.

[45] As a member of a minuscule, unofficial 2-member Carlist minority, Ampuero had little chance to influence the country politics; he was recorded when defending Catholic rights,[46] speaking against attempts to curtail prerogatives of the Biscay self-government[47] and advocating decentralisation of public administration[48] before his term expired in 1884.

At the time Ampuero launched another Basque initiative; 1885 marked the inauguration of Fiestas Euskaras, a Durango-based annual multi-cultural event which followed the pattern of juegos florales.

[61] However, in the unfolding press war between titles which represented competitive currents Beti-Bat sided with the Nocedalista daily, El Siglo Futuro,[62] and in 1883 Ampuero personally voiced against its major opponent, La Fé.

[63] Following the 1885 death of Candido Nocedal he co-signed a homage letter to his son Ramón, who at the time was widely expected to take over the party leadership;[64] however, the claimant opted for an interim solution.

[66] He declined; the official reason quoted was related to formalities, but historians speculate that Ampuero was overwhelmed by scale of internal conflict within the party.

[76] It is not clear whether he again refused the post of the party provincial jefe, which eventually went to Román de Zubiaga; at the turn of the decades Ampuero appeared merely as his deputy.

[88] Ampuero did not take part in nationwide Carlist politics and is barely mentioned in historiographic works on the movement of the 1890s;[89] occasionally the press noted his outbursts against the Integrists, who allegedly sinned against "Dios, Patria y Rey".

[94] At the turn of the centuries he began to appear accompanied by his son José Joaquín, who started to aspire to public posts; in 1900 both were briefly detained as part of governmental precautionary measures related to suspected Carlist conspiracy and minor disturbances in Catalonia.

In 1888 in a periodical Euskal-Erria he published Aita Santu Leon XIII-garrenari, a homage address to the Pope; what made it exceptional was that the eulogy was written in euskara, at the time considered the language suitable for barns rather than for such highly aimed documents.

[96] In the early 1890s he co-organized new Basque festivals, like the one in Iurreta,[97] and sponsored the existing ones;[98] later on he was active in various commemorative committees, like the one to celebrate the anniversary of death of Pablo Astarloa.

[114] Other threads visible in Ampuero's activity were championing Catholic rights against secular attempts of the government,[115] mounting pro-fuerista initiatives with other Biscay deputies and senators,[116] and promoting provincial railway network, the business he was personally interested in.

As a senator he used to take part in grand banquets grouping the party parliamentarians,[118] visited headquarters of Carlist periodicals,[119] attended central religious services formatted as homages to grand defunct Carlists,[120] took part in rallies, e.g. the one in Bilbao aimed against secular schooling,[121] hosted de Mella[122] or participated in local religious ceremonies, e.g. in 1912 – by virtue of his Gipuzkoan representation - in Azpeitia.

A historiographic judgment from the 1980s was that though a genuine foralist, Ampuero remained “ante todo realista”, above all a politician attached to dynastic and monarchist values.

He allegedly failed to re-define the Carlist political offer in Biscay, which in wake of emerging Basque nationalism and ongoing social change contributed to downturn of Traditionalism in the province.