As such, in 1941 he acted as prosecutor in the trial against a group of anarchist members of the Maquis, whom Solís accused of sabotage and of wanting to restore the Republic.

Although technically an "old guard" of the Falange Española, Solís spent much of his professional career as an Army legal officer and as a union steward, so he had little contact with the original fascist movement.

[11] During 1946, as part of his job as the Vice-secretary General of Social Ordinance, he organised the first Trade Union elections and also the first National Congress of Workers.

For example, after 1954 it was no longer necessary to possess a FET y de las JONS card to be able to participate in the trade union elections[18] and even was even an attempt from the Francoist apparatus to attract former anarcho-syndicalist leaders[19] to its core/bosom.

In a short time, he drew up the draft law of principles of the national movement, which sought to provide a legal basis for the single party of the regime and would end up being approved in 1958.

However, some historians have considered that this law actually meant the beginning of the end of the FET y de las JONS as a party, diluting the nationalism within the "movement".

[25] This project, which had already been partially employed in Labour Unions through an internal opening, was complemented by the creation of "associations" within the movement to equip the Franco regime with a certain level of popular participation in the so-called contrast of views.

By October 1958 Solís had already created the National Delegation of Associations with the mission of "widening the bases of accession to the movement to collective groups" and to whose front he had appointed Manuel Fraga Iribarne.

[26] As Minister-Secretary General of the Movement, it was essential that the institutions of the Franco regime adapt to the social changes that were occurring in Spain, promoting a "political development" that complements economic growth.

[27][28] Solís continued to battle in this regard, and in the middle of 1969 he promoted a preliminary draft of the bases of the right of association, although again Franco did not want to promulgate it.

[29] The great power that Solís held – single party, unions, "movement" press and radio – earned him the suspicions of many leaders in the regime.

He also tried to promote the expansion of rights among the employees within enterprises,not within unions, an idea was viscerally rejected by entrepreneurs and some sectors of the government (particularly by Carrero Blanco).

With the appointment of Juan Carlos de Borbón as Franco's successor,Solis led a faction of the nationalist movement that preferred a dictator to a regency with no expiration date .

[36] From June 1975, he once again occupied the position of Secretary General of the Movement in Franco's final government,[37] after the accidental death of his predecessor Fernando Herrero Tejedor.

With Franco seriously ill, on 21 October Solís travelled to Morocco to meet King Hassan II,[40] to try and negotiate an exit and avoid direct conflict between the two countries.

Solís collaborated with his friend Colonel Enrique Herrera Marín – Spain's military attaché in Buenos Aires – on the steps of the transfer of exiled Argentine President Juan Domingo Perón.