Carroll was signed for an undisclosed fee, thought to be around £4m, and has signed a three-and-a-half year deal in South Wales.
The midfielder spent the 2014/15 season on loan at Swansea, where he made 18 appearances in the side that finished eighth in the top-flight.
The former England Under-21 international has become Swansea’s third signing of the window, after Luciano Narsingh joined last week and Martin Olsson was announced earlier today.
What did Carroll say?
Following his move, Carroll said: “It’s been a couple of years since I’ve been here – there have been some changes – but I’m excited to be back,”
“I know what the club is about too,” said Carroll, who will wear number 42. “I know the playing style suits me so that was a big factor in me coming here.”
He also said that it helped that he knew some of the players from his loan spell, and some of the staff from Tottenham too.
Carroll learnt his trade in Tottenham’s academy, joining their Under-16 squad. He went on to make 24 appearances for the London-based side in seven years on their books.
His time at Tottenham was disrupted by loans to Leyton Orient, Derby County, Queens Park Rangers and Swansea.
Where does Carroll fit in the side?
Carroll has played just one minute of Premier League football this season, so it’s unlikely that he’ll slot straight into the starting lineup.
Youngster Jay Fulton has played 626 minutes in Swansea’s midfield this season, usually at the base of midfield, but he was recently demoted to Under-23 duty.
It’s possible that Carroll could displace Fulton, and with Leon Britton not getting any younger he could play at the base of a three-man-midfield if Paul Clement chooses to deploy that formation.
However, Carroll isn’t the holding midfielder Swansea are in dire need of, as they need a defensive expert to protect their weak back four.
Carroll could make his Swansea debut against Liverpool at Anfield on Saturday, at 12:30.