The full-back, 29, is on the cusp of his 200th appearance for the Falcons, who he joined as an academy player and made his first-grade debut in 2007.
He played his junior rugby for Consett and Barnard Castle school.
"I just wanted to know if Newcastle were keen to keep me because I am happy here and didn't want to go anywhere else," said Tait.
Tait, whose deal at Kingston Park is described as "long-term", has been selected 14 times in the Premiership this season and scored two tries.
"He has turned in extremely consistent performances which are right up there at the top," said director of rugby Dean Richards.
"He is a guy who doesn't shirk away from hard work. We're delighted he has pledged his future to us."
Alex Tait has signed a new contract with Newcastle Falcons, although the length of the deal is undisclosed.