Mayo was the 2006 Central American and Caribbean Games champion in the high jump and competed at the Pan American Games in 1991, 1995, 1999 and 2007, which included a bronze on his second appearance at the competition. He was a four-time champion at the South American Championships in Athletics (1991, 1995, 1997, 2005) and a three-time gold medallist at the South American Games – this includes the 1998 South American Games where he also won the triple jump title and the long jump silver medal. His mark of at the 1994 South American Games is the current Games record. He was a frequent participant at the Ibero-American Championships in Athletics and was the gold medallist there in 2000 and 2002.