In October 2000, Bradley played for the Republic of Ireland national football team U16s in a qualifying tournament in Riga for the 2001 UEFA European Under-16 Championship where he came up against Andrés Iniesta.
After a loan spell at Dunfermline Athletic, where he made five appearances, he returned to Ireland and signed for Drogheda United in March 2005.
In his first season at United Park Stephen picked up an FAI Cup winners medal as Drogheda beat Cork City 2–0 in the final at Lansdowne Road.
In January 2009 Bradley signed for Michael O'Neill at Shamrock Rovers[3] and made his debut on the opening day of the 2009 League of Ireland season in a 0–0 draw away to Bray Wanderers.
[5][6] At the end of the 2010 League of Ireland season Bradley was released by the Hoops and moved across the M50 to join Pete Mahon at St Patrick's Athletic.