The 'Swans' were in need of defensive reinforcements after something of an exodus this summer. Federico Fernandez, Alfie Mawson, Jordi Amat and Kyle Bartley all left the club following relegation from the Premier League.
Carter-Vickers has been capped four times for the senior USA team, and signed a new contract earlier this year to seal his long term future at Tottenham.
Last season he split his time on loan at Sheffield United and Ipswich, both in the Championship.
On joining Swansea he said: "I am super excited. Swansea is a massive club and I can't wait to get out training with the boys.
"When I spoke to the manager [Graham Potter] he told me how they wanted to play. I have watched them play a few times this season and you can see they play good football. I am looking forward to being part of that."