His business partner Aaron Young was worst hit, losing out on nearly $1m.
Joshi persuaded him he could get hold of cheap high-end cars from Japan and Young gave him $662,000 to buy 21 vehicles and a yacht.
Only two cars were ever delivered and Mr Young had to pay extra to secure loans to keep them.
In 2012, Joshi also managed to dupe his doctor - who was granted interim name suppression - out of $477,000.
He told the man the money would cover four luxury cars but he quickly ran out of excuses when there was nothing to show for the cash.
Eventually he persuaded two car dealers to let him borrow a couple of vehicles that "fit the description" and he removed the batteries and number plates before showing them to the doctor.
Joshi lied that they could not be handed over because of the missing parts and when the victim left he returned the cars to the dealers.
The doctor only got back $20,000 of his original stake, and no luxury vehicles.
"You even stole from your mother", Justice Murray Gilbert said.
Joshi swindled $9000 from her credit card and later falsified his parents' signatures to obtain funds from a finance company.
During sentencing today Justice Gilbert asked what the defendant had done with all the money.
"I have no instructions on that," defence counsel Peter Kaye said.
Joshi was adjudicated bankrupt in February last year and the judge accordingly opted not to order reparation.
Justice Gilbert said the offending "involved a considerable level of planning and premeditation" and the 33-year-old felt no sympathy for his victims.
"There's no genuine remorse here," he said.
"You wrote a letter to probation minimising your involvement and culpability."
One of the victims spoke outside court about how his dealings with Joshi cost him his business and his relationship.
He described the defendant as "a very clever guy" who loved to be seen as a man about town, and he was sceptical about whether a few years in prison would change his ways.
