Nicknamed 'Shy One' as a youth, He was the 7th in a family of 10 children, and made his professional debut in 1939, following older brothers Tomás & Domingo into the game. After a year of scoring goals for home-town side SD Erandio Club in the 2nd division, the 19-year-old joined Athletic, then Spain's most successful club, as they looked to rebuild in the wake of the Civil War – which had claimed the life of His brother Domingo.
He averaged a goal a game in his first full campaign, 1940/41, yet had to abandon his sporting duties from 1941–42 to perform military service. He returned a year later to fire Athletic to a domestic double in 1942/43, hitting the only goal in extra time in the cup final against Real Madrid.
It was the first of 5 Spanish Cups that He would lift with Athletic, and he reached a scoring peak with 38 in the 1950/51 Liga. It would be 40 years before Madrid's Hugo Sánchez equalled that haul.
In a match at Málaga CF, he made a point of booting the ball wide after rounding the keeper since he felt he had kicked the No1 on the way through – Málaga later presented him with a gold medal to honour this most sporting of gestures.
"He was a top sportsman but his value as a person was immeasurable," said Athletic goalkeeping great José Ángel Iribar. "Every Athletic player knows about his kindness. He was a great example to everyone. He is the embodiment of the spirit of Athletic."