Edwin McLaren, from Quarriers Village in Renfrewshire, was found guilty of property fraud scheme, which involved duping vulnerable victims in financial difficulty to sign over their homes, police said.
The 52-year-old, who previously worked as a financial adviser, is said to be the "brains behind the scheme" and was convicted of 29 charges at a High Court in Glasgow in a trial which began in September 2015 and lasted over 320 days.
The lengthy trial is estimated to have cost about £7.5m, with more than £2.4m in legal aid paid for defence lawyers.
His wife Lorraine McLaren, 52, was only convicted of two charges of being involved in the scam to the extent of £128,000 and one charge of mortgage fraud, claiming she only signed documents when her husband told her to.
The court heard how McLaren targeted people under financial pressure, often after placing adverts in newspapers for two companies - Property Solutions and Homesale Solutions.
Presenting himself as a financial adviser and a millionaire businessman with hundreds of properties, hr would tell his victims he would sort out their financial difficulties, usually in the form of a loan or leaseback agreement.
Many thought they were releasing equity from their homes but McLaren had them sign paperwork which transferred full ownership of their property.
The properties were then sold on to a third party and sale proceeds paid into an account controlled by McLaren, who also raised mortgages against the homes.
The court heard how the McLarens used the proceeds to fund an extravagant lifestyle in the upmarket Scottish enclave of Quarriers Village, where the couple lived in house worth more than £700,000.
He would holiday in Dubai and had a yellow Bentley, however his assets have now been frozen under the proceeds of crime act.
He was said to have shown no sign of remorse.
Detective Superintendent Andy Lawson described the case as “extremely complex inquiry” and “one of the largest, most complicated property fraud investigations ever carried out in Scotland”.
He added that it took more than four years for detectives to unpick the network of banking transfers and legal documentation for 24 properties that made up the £1.7m fraudulent conspiracy spanning a six-year period.
”Undoubtedly, the shameless actions of Edwin McLaren, who had the ability to persuade and dupe innocent victims and professionals into agreeing to his dishonest scheme, has wreaked devastation on many people, whilst they continued to live a life of luxury.
“These are heartless individuals, driven by greed, who were ruthless financial predators, and who despite pleas for help from their victims, chose to disregard them as they focused on their financial gain,” said Lawson.
Edwin McLaren was remanded in custody after he was found guilty of 29 charges.
His wife has been released on bail.
The pair will be sentenced next month.