Day previously played all of his professional career at Sale except for a short term contract at French giants Stade Francais. In the 2005-6 season Day played as a replacement in the final as Sale Sharks won their first ever Premiership title.He has now made more than 100 appearances for both Northampton Saints and Sale Sharks. In this time he has won:- 2 Premiership Titles (once a losing finalist) 3 European Shields (once a Heineken Cup losing finalist) 2 National Cups (three times a losing finalist) 1 Premiership A League TitleIn 2014 he was voted Northampton Saints Player of the year as part of the 2013/2014 Double Winning Squad.He has represented England Saxons, Captained England Under 21s, England Under 19’s and represented England schools.

He is currently Vice Chairman of The Rugby Players Association.