He was third in the 800 metres at the 2006 Ibero-American Championships,[6] won his first national title over 1500 m, and represented Venezuela at the 2006 Central American and Caribbean Games.

[5] He won two medals at the 2006 South American Under-23 event, winning the 1500 m and coming a close second to Brazil's Kléberson Davide in the shorter race.

[9] He gained selection for the Venezuelan team at the 2007 World Championships in Athletics held the following month and he improved his 800 m best further by running a time of 1:46.33 min in the heats.

Villanueva improved his 1500 m national record to 3:38.29 minutes at a meeting in Barcelona in July 2011 and gained selection for the 2011 World Championships in Athletics in Daegu, South Korea.

In the final he finished in eighth place, which was the best ever performance by a Venezuelan track runner at the world championships (improving upon William Wuycke's run in 1987).