Billy Rees was a determined forward who started with his village team of Blaengarw and he was a miner before he signed as a professional for former Spurs keeper Cyril Spiers, who was manager of Cardiff City in 1942.

His early career in Wales was with Caernarfon Rovers while working as a miner in two local collieries.

Moved to Cardiff City in 1942, signed by Cyril Spiers (ex-Spurs goalkeeper and then manager of the Bluebirds), with the inside right going on to play in war-time games for the Welsh club.  They were impressed by his ability and he signed professional in 1944.  Turned out in an international for Wales v England in 1944-45 at Cardiff fifteen months after signing for Cardiff.  Billy scored 49 goals in 58 games up to the end of the war and in 1946-47, the club won the Third Division South championship with him leading the line.

Rees had been a regular scorer at Cardiff, but when things weren't going right for him at White Hart Lane, he asked for a move and in the summer of 1949, Billy came to Tottenham for a five figure fee.  When he left Cardiff City he had scored 33 goals in 101 league matches,  So, when he signed for Tottenham in June 1949 for £14,000, a lot was expected of him. 

His debut was delayed because of a series of little niggling injuries, but scored on 22nd October 1949 against Southampton reserves, with his first team debut coming in the away game against Chesterfield in a 1-1 draw.  Scored his first goal in the next game four days later at White Hart Lane ... against Cardiff City !!  His first season ended with four goals in 12 reserve matches, 11 first team league appearances with three goals scored, along with two cup ties played.  Was a useful member of the Second Division championship team in 1949-50.

Leyton Orient signed Billy in June 1950 for £14,500, where he stayed for six years and scored 66 goals in 198 games.  Left to join Headington United (who became Oxford United) of the Southern League in December 1955 and ended his time in the game at Kettering Town.

Back in his home town, Rees took up running a general store and worked in a pharmaceutical factory as a plant operator, while keeping pigeons in his spare time.

Lived in Llangeinor near Bridgend until his death in a Cardiff hospital on 25th July 1996 after a sudden illness.