Nastase was initially suspended while the ITF launched an investigation following racially insensitive remarks he made about 23-time grand slam singles champion Serena Williams’ unborn child in April.
The 71-year-old also hit the headlines for the wrong reasons in the same month when he was ejected during Romania’s Fed Cup match against Great Britain in Constanta, having initially refused to leave the court.
Nastase was given a second official warning as a result of his behaviour courtside in his role as Romania captain after Sorana Cirstea took a 2-1 lead in the second set of her rubber against Johanna Konta.
The ITF has found him guilty of making abusive and threatening comments to members of the British team and match officials, as well as a member of the media.
Nastase was also found guilty of making advances of a sexual nature towards GB captain Anne Keothavong during the tie in Romania.
The ITF on Friday revealed that Nastase was in breach of five articles of its Fed Cup Welfare Policy and is banned from acting in any official capacity in an ITF team competition until the December 31, 2020.
Two-time major singles champion Nastase is also unable to act in an official capacity in individual ITF competitions and on official ITF Tennis Circuits during that period.
Nastase has been fined US$10,000 and will not be allowed entry to ITF competitions – which do not include grand slam tournaments – whatsoever until the end of next year.
The Romanian Tennis Federation and Nastase have 21 days to appeal against the decision to an independent tribunal.