Tomás graduated in Veterinary Medicine, from the Complutense University of Madrid, in 1979. After obtaining a Diplomate in Public Health, from the National School of Departmental Health of Valladolid in 1981, Tomás joined the Corps of Official Veterinarians, by national opposition, in 1985. He thereafter obtained a Degree on Food Technology from the University of Burgos in 1998.

He began his professional activity in 1980, practicing in different municipalities in the province of Burgos. In 1990 he joined the Agriculture and Livestock services of the Junta de Castilla y León and in 1992 the Public Health services, performing since 1995 the Technical Sanitary Directorate of the Incarsa slaughterhouse in Burgos, until 2012 when he was assigned as Head of the Public Health Unit in the Government Sub-delegation of Burgos, a position he currently occupies.

Tomás Fisac ​​is currently president of the Official College of Veterinarians in Burgos, a position he has led since 2000. Tomás was president of the Council of Veterinary Colleges of Castilla y León between 2006 and 2016.

He is also secretary of the Governing Council of Cajaviva-Caja Rural and president of the Fundación Caja Rural de Burgos.