Born in Barcelona, Catalonia, Ramallets signed for FC Barcelona in 1947 at the age of 23, from Real Valladolid, where he also spent his first season after being purchased, on loan. He returned to the club to play second-fiddle to Juan Velasco, making his La Liga debut in a 2–1 win against Sevilla FC on 28 November 1948. Although this was his only appearance during the season he eventually became the starter, being an essential defensive unit as his team – then named Club de Fútbol Barcelona – went on to win six leagues and five domestic cups; in the 1951–52 campaign, as Barça won five major trophies, he contributed with 28 league games, being awarded his first Ricardo Zamora Trophy.
In the 1960s Ramallets coached several clubs, including old acquaintance Valladolid. In the 1963–64 season he led Real Zaragoza to the fourth place in the league, the Spanish Cup and the Inter-Cities Fairs Cup – a competition he had won twice as a player with Barcelona – winning over fellow league side Valencia CF in the latter.
Ramallets played 35 games for Spain during 11 years, making his debut against Chile on 29 June 1950, during the 1950 FIFA World Cup in Brazil. During the tournament he earned the nickname The Cat of Maracaná, helping the national side to the second group stage.