His great-grandfather José Soler Mallent originated from the town of Albuixech, few miles north of Valencia;[2] he married Ramona Torrent Rois, yet there is no information on his occupation.

At some point the couple moved to the Levantine coastal town of Burriana, the birthplace of Juan Bautista's grandfather, Vicente Soler Torrent (1798–1871).

[10] It seems that Juan Bautista and his siblings were raised in poverty; he learnt to read and write in the army, as in 1898 he volunteered to spare conscription to his older brother Manuel, who apparently was more needed in the family economy.

There is confusing information on a José, who allegedly died at the early age; he reportedly shot himself when playing with a pistol of his father, yet it is not clear whether he was indeed Soler's son.

Juan Bautista Soler Martínez, a Carlist like his father, after the Civil War emerged as the provincial Falange secretary in Castellón;[18] until death in 1970 he was concejal of the Burriana ayuntamiento.

In the early 1920s Soler and other local entrepreneurs led by Jaime Chicharro were busy lobbying for financial aid; in 1921 their efforts resulted in a Royal Order which marked significant state resources for development of the harbor[32] and envisaged also major investments which would connect the port with the national railway network.

[40] Soler also got engaged in show-business; he was among major shareholders of Cifesa[41] and held stakes in Plaza de Toros and in Teatro Principal, both in Valencia.

[42] In some 25 years he turned from barely literate employee in petty family enterprise into a provincial trade tycoon running an international business and operating commercial offices in London.

At this opportunity he was among these who co-founded the local Somatén, an auxiliary civil militia promoted by the regime,[45] and contributed to extensive implantation of primoderiverismo in the Castellón province.

Following some sort of consultations with the Burriana "vox populi", which most likely stood for local business and political elites,[55] in February 1930 the Berenguer regime appointed him the mayor of the city.

[56] In January 1931 members of the city council confirmed his post during an internal voting,[57] but there is little known about his tenure, except that liberal press lambasted his appointment as demonstration of reactionary caciquismo.

[58] However, during final days of the monarchy Soler seemed rather politically bewildered; he entered the Castellón provincial board of a republican party[59] but in the April 1931 local elections to the town hall he ran as a Conservative.

However, it appears that from the early 1930s he was already engaged in the newly united Carlist political organization, Comunión Tradicionalista; most likely he was introduced by one of the pre-1919 Jaimista leaders in Castellón, Chicharro.

[66] It is not exactly clear what mechanism produced his 1933 nomination to head of the provincial Carlist organization in Castellón; it was probably the result of his wealth, prestige and personal friendship with Chicharro.

[69] In the mid-1930s he rather engaged in the increasingly bitter social conflict; international crisis produced decline in orange exports, which in turn resulted in reduced demand for labor and lower pay.

He made it into history of electoral campaigning in Spain as the first one to use aircraft for propaganda purposes,[73] but with 11,800 votes gained he failed to earn the Cortes mandate.