The two clubs agreed a fee believed to be upwards of £8million, with the player penning a long-term contract at White Hart Lane.
The 23-year-old is suspended for the first two games of the new season following his sending-off against Fulham at the end of last term.
A statement from Tottenham: "We are delighted to announce that we have reached agreement with Newcastle United for the transfer of Sebastien Bassong to the club, following the player successfully completing a medical examination and agreeing personal terms."
Redknapp: "I like Bassong, he is a young player with a good future and a good central defender."