The 33-year-old pacer, who didn't find takers during the IPL auction in February, will now join fellow Australians Chris Lynn and Brad Hogg at the Kolkata-based team, which is currently at the third spot with 12 points in the IPL table.
"Pleasure to welcome @shaun_tait32 to @KKRiders family. Welcome Taity!," Kolkata chief executive Venky Mysore wrote on his Twitter page.
Tait joined the team yesterday and was present at the training session for KKR, who will take on Rising Pune Supergiants on Saturday.
Tait, who bade adieu to ODI cricket in 2011, had earlier played for now-defunct Rajasthan Royals, taking 23 wickets at an average of 27.82 in 21 matches. He also played in Australia's Big Bash league.
He took 62 wickets at an average of 23.56 in 35 ODIs and 28 wickets at 21.03 in the 21 T20 Internationals that he played for Australia.