Arnulfo Vallejos Valles was born in 15th August, 1940, in Tagbilaran, Bohol.
Valles was an active sprinter during most of the 1960s. He was a PSIAA (Public Interscholastic Athletics Association, predecessor to the Palarong Pambnansa) stand out with William Mordeno.
He represented the Philippines at the 1964 at the Tokyo Olympic Games finishing 7th in heat 3 in 11.1 (11.21a). And also 7th in heat 3 of the Mens 4×100 in 41.7 his team mates were Miguel Ebreo, Claro Pellosis and Rogelio Onofre.
At the 1966 Asian Games in Bangkok with Rogelio Onfore, Remigio Vista, and William Mordeno he won a bronze medal in the 4×100 in 41.3. The Philippines however failed to defend the title they won four years prior.
Valles best time came in 1967 when he clocked 10.5 in the 100 meter dash. A formidable curve runner he clocked 21.6 the following year in the 200 meter dash.
Valles met his wife Nelia at the 1964 Asian Games, they had two children a daughter who became a nun in Italy, and a son who works in Dubai.