He was the second-born of three children (Álvaro and Mercedes) from the marriage of Serafín Muñoz Ruiz, born in Jerez del Marquesado (Granada) and Florinda Ramonet Sindreu, born in Martinet de Cerdanya (Girona). She was the niece of the owner of the El Barato department store in Barcelona.
Due to the good relationship forged with the Franco regime, Julio and his brother Álvaro purchased several factories at very reasonable prices.
During the nineteen forties and fifties they purchased Can Batlló industrial complex, the Unión Industrial Algodonera, the El Águila and El Siglo department stores, part of the estate of the Marquis of Alella, the palau Robert and the hotel Ritz. They also founded several companies, amongst which the Compañía Internacional de Seguros (CIS).
His success and social climbing were not only due to his entrepreneurial activities. In 1946 he married Carmen Villalonga, the daughter of Ignacio Villalonga, the owner of the Central Bank, with whom he had four daughters.
In 1986, due to legal problems derived from the bankruptcy of the Compañía Internacional de Seguros (CIS), Muñoz Ramonet moved his residency to Switzerland where he died.
