His father and two brothers were assassinated by the Republican forces at the start of the Spanish Civil War.
He fled to San Sebastián where his uncle was the governor before settling in Zaragoza.
[2] In 1965, Sainz de Varanda opened his own law firm and soon became Dean of the Zaragoza Bar Association and the Consejo General de la Abogacía Española [es], the General Council of Spanish lawyers.
He was a specialist in Aragon's fueros, widely believed to have been abolished in the 1707 Nueva Planta decrees.
As the first democratically elected mayor of Zaragoza in 1979, he worked on infrastructure and development and reclaimed the Aljafería palace from the military and oversaw the creation of the Pablo Gargallo Museum.