An aggravating factor was Mr Hart's "poor disciplinary history", which included seven previous findings against him.
One for "gross overcharging" was 30 years old, but identical in nature to the current case, and he was censured for a verbal altercation with a fellow lawyer in 2006.
Mr Hart was found guilty of unsatisfactory conduct for overcharging on two occasions in 2010 and again a year later.
Two other findings of unsatisfactory conduct for failing to pay expert witnesses - again described as identical behaviour to one of the charges in the current case - were made just last month.
The pattern of behaviour meant the tribunal had "no confidence in either his rehabilitation or protection of the public by ensuring there is no risk of reoffending".
"We accept that striking off, particularly in a practitioner of such seniority, is a last resort response," said Judge Clarkson.
"Having weighed all the evidence and submissions it is the tribunal's unanimous view that the practitioner is no longer a fit and proper person to practise as a barrister or solicitor."
The consequences could be even greater for the 71-year-old veteran who has lost a property empire, a fleet of luxury cars and his career in just a few months. He has lost a "lifetime of earnings" because of the collapse of his rural property portfolio in Waimauku, for which he owes $30 million to the ANZ National Bank and was charged $200,000 interest each month.
Debt collectors also seized luxury cars, excavators, tractors and computer printers to settle a $1.5 million debt with GE Finance.
The feisty lawyer tried and failed to stop the mortgagee sale of the 952ha of prime real estate, described as "a rare opportunity to secure one of the largest privately owned land holdings north of Auckland" sold in individual lots.
Despite the auction, Mr Hart refused to leave and let the new owners move onto the farm by filinga succession of injunctions and caveats.
Neighbours David and Joy Steele purchased the 40ha block last month but were forced to take legal action when they were stopped from taking control.
Earlier this week, Justice Geoffrey Venning ruled Mr Hart must vacate immediately, remove all livestock and not re-enter the property. He has since left.
Mr Hart's pattern of dragging out matters was also strongly criticised by Judge Clarkson, who described the "arrogant and derisory manner" in which he approached any complaint about his conduct.
In this case he had nine different lawyers and did not attend the disciplinary hearing, which was described as "unprecedented".
Mr Hart was ordered to pay 85 per cent of the Law Society's $116,000 costs - a total of $98,000 - despite his "financial ruin".
Struck off
Barry Hart was found guilty of three charges of professional misconduct in July.
* He charged a client's family $1000 an hour despite much of the preparation work being done by a junior lawyer who had been practising for only two months. On one occasion, the fees were charged for "waiting time in court" and totalled $35,000 - $20,000 more than a Queen's Counsel said they should have been.
* Failed to inform a private investigator that a $4682 bill would be paid only if he got legal aid.
* Refused to disclose a file to the Law Society's standards committee after a complaint over costs. Despite several extensions of time, Hart delayed handing the file over for more than a year. The tribunal found Hart had prevented the standards committee investigating the complaint.
* Seven previous disciplinary findings against Mr Hart.
- Additional reporting: Alanah Eriksen
