Billy started out as a schoolboy in the RotherhamAcademy, but elected to join his home town side of Sheffield United at the age of 16. The young striker made two substitute appearances for the Blades, but didn't really feature in Neil Warnock's plans, and came to Diamonds on 21 January 2005 on an initial one month loan deal. After scoring two goals in five games, his loan period was extended to three months. His time at Diamonds will be fondly remembered not only for the 9 goals in just 16 appearances, but for the late winner in the crunch derby match against NorthamptonTown. In March 2005. His valuable goals saw Diamonds avoid relegation that season.
He returned to Sheffield United on 24 April 2005, but a £100,000 transfer deal with Scunthorpe United in August saw him move to the League One side. His goalscoring continued unabated with 56 goals in 95 games over two seasons which culminated in the clubs promotion to the Championship. With a number of clubs showing interest, he rejoined his beloved Sheffield United on 4 July 2007 for a £1,500,000 fee, but his form dipped again. During September 2009, he went on a season long loan to fellow Championship side Doncaster Rovers.
