Tomás was born in Villanueva de Gállego, a village located 11km from Zaragoza. When Tomás was born, his father was already a teacher in Villanueva, in the same school that his grandfather had left vacant when he died. It was only a year earlier that his father had married his mother - Teresa Alvira - a girl from Lanaja (Huesca). They were first cousins and had to ask for a canonical dispensation because of their relationship.
He was 2 years old, when his father passed a teaching competition in Zaragoza and the whole family moved to the Aragonese capital. There he went to the school of Montemolin, next to the street Miguel Servet.
The young Tomás gave his first class when he was only 9 years old. This was because his father asked him to give a class to the seven-year-olds. He wanted to see how he handled himself: "Explain the angles to him," his father told him, pretending to leave class. Tomás went to the blackboard and drew two circles and four stripes, as if they were two clock faces. And he began to explain to them the angles: right, sharp and obtuse: "Look, this is three, five, six".
After completing his Bachillerato or A-levels at the Instituto de Zaragoza, Tomás enrolled for Chemistry at the Faculty of Science of the University of Zaragoza in 1922. From 1928 onwards, he taught at several schools.
In 1934 he became Director of the Instituto de Cervera del Río Alhama, whose faculty was made up of professors of all kinds of political ideology: from the radicals on the left to those on the right, which reveals his spirit of dialogue and conciliation.
During the first weeks of July 1936, he moved to Madrid for the Institute's associate competitions. He was living in El Rolmo, a small hostel with windows overlooking the Gran Via. He began the competitions with a good start: at the end of the fourth exercise, he was only beaten by one opponent. He already had his future planned: as soon as he finished the final test, he would return to Zaragoza to marry Paquita, a former student of his father's in the "José Gascón y Marín" school group, whom he had known since January 1926 on a study trip to Barcelona.
Shortly afterwards, he met José María Albareda, an old acquaintance from the University of Zaragoza, and introduced him to two young gentlemen, faithful of Opus Dei: the Argentinean engineer Isidoro Zorzano and the doctor from Madrid, Juan Jiménez Vargas. He begun to study with them in the guesthouse where Albareda is staying.
On September 1, 1937, he met Fr. Josemaría Escrivá, the founder of Opus Dei, from whom he heard for the first time about the possibility of being a saint in daily life, in professional work, both in celibacy and in marriage. In 1947, Thomas was the first person to set out to live the Christian ideal in marriage according to the charism of Opus Dei.
Shortly after meeting St. Josemaría, he decided to cross the Pyrenees on foot, along with other fugitives, and to join his family, who had remained in the other part of Spain. Because of the hunger and long walking time, Tomás lost his strength and the guide ordered that they leave him there commenting "You can't jeopardize the entire expedition." But after a conversation with St. Josemaría, the guide changed his mind and agreed to stop for a while to rest. In this way they finally reached the other side.
On June 16, 1939, Tomás married Paquita in the church of San Gil in Zaragoza. It was also in this year when he started teaching at the Ramiro de Maeztu. In 1941, he became a professor in the same institute. In 1945 he obtained the chair of the Institute of Natural Physical Sciences. Between 1951 and 1958, he was Director of the Colegio Infanta Maria Teresa School - the Civil Guard's College for Orphans ; it was there that he put his pedagogical theories into practice, unrelated to any elitism or discrimination. In 1957, he was appointed National Councillor for Education.
Later on, he took part in the creation of the Fomento de Centros de Enseñanza. From 1973 to 1976, he was the Deputy Director of the Experimental Centre of the Institute of Educational Sciences (ICE) of the Complutense University, and then Director of the University School for the Promotion of Teaching Centres. Its greatest innovation was the creation of the Living Classroom.