Born in Tonna, he schooled at Cowbridge Grammar, where he met a lifelong friend Brian Sparks, who also became a Neath and Wales international and who studied with Maddocks at St Luke's College, Exeter.
Sparks, who turned to Rugby League with Halifax after gaining seven caps, also played with Maddocks for Devon County and was best man at Maddocks' wedding. He said: "Keith was a gentleman in the true sense of the word. We called him 'Flyer Maddocks' and his speed was just fantastic."
His only cap was against England at Cardiff and Referee Sandy Dickie of Scotland made an amazing decision to rule Maddocks offside when he was the furthest of the 30 players from the action. Fenwick Allison goaled the penalty for the only score of the game and Maddocks, who received no passes, was dropped.
He soon left both Wales and the sport, teaching English at St Boniface's School in Plymouth, near the area that his wife Marjorie, who predeceased him four years ago, had come from.
Born Tonna 16th June 1927. Died Plymouth 5th June 2005.