Born in San Sebastián, Gipuzkoa, Basque Country, Fuentes joined Real Sociedad's youth setup in 1979 from La Salle CD.
[2] In what was a transitional period for the club as their successful squad of the decade began to break up, they reached the quarter-finals of the 1988–89 UEFA Cup but lost out to VfB Stuttgart in a penalty shootout with the player, again introduced as a substitute, missing a good chance to win the tie;[2] it was around that time that he was converted into a right-back by manager John Toshack.
[6] Fuentes won one cap for the unofficial Basque Country regional team, in a 1–1 friendly draw to Paraguay on 22 December 1995 held at the San Mamés Stadium.
From July 2005[8] to June 2007 he acted as president to Real Sociedad, quitting his post for personal reasons[9][10] with the team on the verge of relegation, an eventuality which was confirmed a few weeks later.
[11] He was replaced in the interim by María de la Peña, the first woman to hold such a position at the club,[12] albeit she stepped aside a matter of months afterwards to be succeeded by Iñaki Badiola.