His political climax fell on the years of 1905–1916, when during 4 consecutive terms he represented the district of Aoiz in the Congress of Deputies, the lower chamber of the Cortes.

It is not clear what was the size of combined rural estates owned by the couple; upon inheriting their possessions, Tomás was mentioned in the press as a very wealthy man.

[33] Already as a student Tomás got involved in right-wing para-political engagements; he was among co-founders of Juventud Católica of Seville and became secretary of the local Asociación de Católicos.

[34] During final years of the Isabelline monarchy in the late 1860s he reportedly "took active part in the battle of ideas",[35] the turmoil which eventually ended up in so-called Glorious Revolution.

He engaged in reconstruction of shattered Carlist structures in the capital, which soon translated into attempts to animate the local branch of Comunión Católico-Monárquica, the pre-war party organization.

[45] Since the mid-1880s Carlism was increasing paralyzed by a conflict between the claimant Carlos VII and the chief theorist of the movement, the charismatic Ramón Nocedal; apart from personal rivalry, it was conditioned by different visions of political priorities and the strategy to be adopted.

[46] As the breakaways controlled two key Traditionalist newspapers, La Fé and El Siglo Futuro, the loyalists remained with no Madrid-based daily which could serve as the semi-official national party mouthpiece.

Domínguez Romera and Cerralbo labored to create an alternative press platform; their works were crowned with success in 1889, when the new Carlist daily El Correo Español was launched.

[47] During the electoral campaign of 1891 Domínguez stood as a Traditionalist candidate for the Cortes in the Riojan district of Santo Domingo de la Calzada, where together with his wife he owned some real estate; he was defeated by a small margin by the local liberal cacique Amós Salvador, the nephew of Mateo Sagasta.

[63] His most vehement activity was related to the so-called Ley del Candado, legislation endorsed by the liberal government in the late 1900s and intended against religious orders; like the entire minority, he did his best to block the initiative.

[70] At the turn of the decades he interchanged with Cerralbo, Feliú and Vazquez de Mella when presiding over banquets,[71] though he was noted for presence in close sessions rather than in open rallies.

[75] It is not clear what was the position Domínguez adopted during internal rivalry between so-called Cerralbistas, followers of the 1899-deposed Cerralbo, and the party leaders in 1899-1912, Matías Barrio y Mier and Bertolomé Feliú y Pérez; given his nominations it seems he remained on good terms with both factions.

[78] However, when in 1919 the long-brewing conflict between de Mella and the claimant Don Jaime translated into an open confrontation, Domínguez decided to stay loyal to his king.

[79] At the time he was already over 70 and in the party he was gradually being replaced by his son, Tomás Domínguez Arévalo; he did not take part in the grand 1919 meeting known as Magna Junta de Biarritz, supposed to set the future direction of Carlism.

Scholars claim that he welcomed the Primo de Rivera coup of 1923, remained on good terms with the dictatorial regime and with the dictator personally.