His younger brother Iñigo, often referred to as Larrainzar II, was also a footballer, and both played at Osasuna.
A product of hometown CA Osasuna's youth ranks, he totalled seven La Liga appearances from 1988 to 1990.
In his third season he helped with 14 games and one goal to help the Navarrese club to finish fourth and qualify for the UEFA Cup[2]– although younger, his brother Iñigo was already an essential member of the squad.
With Osasuna in the Segunda División, Larrainzar dropped down to Segunda División B and signed for Málaga CF, helping the side to return to the top flight in just two years.
[3] In 2002–03, prior to Málaga's Intertoto Cup conquest, Larrainzar returned to the second tier with Levante UD,[4] but retired at the end of the campaign at the age of 33.