Midfielder returns to Inchicore following spell in Finland's top flight as Liam Buckley confirms two more signatures from last season's squad
McFaul, who played under Pat's' manager Liam Buckley at Sporting Fingal, was with the Saints in 2011 before moving to the top division in Finland.
The Dubliner played for three seasons in England with Notts County and, after a short spell in USA, he returned to Ireland to join UCD in 2007.
After losing James Chambers and Sean O'Connor to Shamrock Rovers, McFaul becomes the third midfielder to join the Inchicore club after Killian Brennan and Conan Byrne sealed their moves to the Saints yesterday.
"Delighted to announce that I've signed for @stpatsfc for the 2013 season," McFaul tweeted last night. "So excited for the new season with a top class squad in place!"
Meanwhile, two more of the 2012 squad have committed their short-term futures to the club.
Midfielders John Russell and Jake Kelly have both put pen-to-paper for the 2013 season.
The duo follow Chris Forrester, Jake Carroll, Ian Bermingham, John Russell, Ger O’Brien, Conor Kenna, Kenny Browne, Anthony Flood and Christy Fagan in re-signing for the new campaign.