Alfarero didn't play organized basketball until his senior year at Lanao del Norte National Comprehensive High School.
He was an alternate on the Philippine youth team under coach Turo Valenzona in 1980 and a reliever on the national squad that saw action at the Asian Basketball Confederation (ABC) championships in Calcutta in 1981.
He joined Elmer Reyes, Ed Cordero and Franz Pumaren on the Philippine team that won the gold medal at the Southeast Asian Games in 1981.
His most memorable experience was playing as the starting center for the Ron Jacobs-coached Philippine team that captured the Asian Youth crown in Manila in 1982.
In 1985, Alfarero turned pro and wore the Great Taste colors after a brief stint with Northern Cement as a PBA guest club the year before.