Castro was born in 1959 and grew up in
Shady Side, Maryland. He attended the
University of Maryland with the intention of earning a
scholarship as a baseball
pitcher, but contracted
mononucleosis during his first semester which caused him to miss the try-outs. After he recuperated, Castro decided to try out for the
football team as a
walk-on placekicker, a position he had played in high school. During his sophomore year, he was offered a scholarship. He joined another Maryland walk-on that season who gained national recognition,
Charlie Wysocki, who was the nation's rushing leader in 1979. In 1979, Castro tied the NCAA record for most
field goals in a half, with four against
Mississippi State. In the fourth quarter of that game, he made a fifth field goal. He concluded his collegiate career in 1980, and as the end of 2008 season, he remains the school's fourth-ranked player in career
punting yards (8,584), seventh-ranked in field goal percentage (69.2%), and tenth-ranked in career field goals (27). ==Professional career==