[1] Hailing from Cabangan, Zambales, del Rosario started as a sprinter but shifted to weightlifting.
Standing 1.62 meters (5 feet 4 inches) high, del Rosario first took part in the 1948 Olympic Games in London.
[2] At the 1952 Summer Olympics, del Rosario set a world and Olympic record by lifting 105 kgs in the military press portion of the men's 60 kg event surpassing Iran's Jafar Salmasi lift of 100 kgs.
[2] Del Rosario represented the Philippines at the 1970 World Weightlifting Championships in Ohio.
He was awarded a gold medal after athletes who made heavier lifts were disqualified for doping.