Jocelyn Dupuis is on trial for fraud and forging documents and is accused of charging the labour organization for tens of thousands of dollars in expenses by using fake or inflated bills.
Witness Renald Grondin defended Dupuis, saying the union knew of his practices and approved of them because he often paid other union expenses out of his own pocket.
Another union official, Andre Kegle, testified that Dupuis paid him $100 a week in cash out of his own pocket when his hours were reduced.
Dupuis served as director-general of the labour federation's construction wing between 1997 and 2008. Grondin testified it became known that Dupuis was the point man for union-related expenses.
Grondin couldn't explain why Dupuis would use such a method of claiming expenses instead of seeking reimbursement by filing proper claims.
The charges against Dupuis are related to events that allegedly occurred in his last 11 months on the job when he filed 43 expense accounts totalling $225,000.
Police have identified 144 bills they say could represent more than $63,000 in fake or inflated invoices at six Montreal restaurants. Of those, half are fake bills with no verifiable transaction record available, police said.
The other half are allegedly inflated, with investigators having tracked down original receipts they say were far less than what was billed for.
A provincial police probe showed that Dupuis didn't hesitate to order $300 or $400 bottles of wine at restaurants. In one instance, he claimed $1,500 for a meal when the bill was $1,100. The meal was on a Sunday in December when the construction wing was officially on holiday.
On a union trip to California and Las Vegas in March 2008, Dupuis claimed $7,800 for four meals for which he did have proper receipts.
The trial has heard that Dupuis was the only union representative who didn't use a credit card issued by the labour group.
Grondin attempted to minimize Dupuis's seemingly extravagant lifestyle, as described by the Crown.
He said the accused's Corvette was "pretty old," that his Ford Explorer "wasn't very new," and that his house was "very, very ordinary."
The Crown reminded Grondin that Dupuis also owned a Winnebago, two Harley-Davidson motorcycles and a BMW.
As for a boat also owned by Dupuis, Grondin described it as a modest craft that didn't even have a cabin.
Grondin compared it to Touch, the now-infamous luxury yacht owned by controversial former construction boss Tony Accurso. The province's corruption inquiry has heard the yacht was often used to entertain government officials and union representatives.
"It wasn't Touch," Grondin said of the accused's craft. "Rather, it was the Don't Touch."
The case has been adjourned until May 16, when Quebec court Judge Denis Lavergne will hear final arguments.
Dupuis will be tried separately on one count of inciting another person to file fake documents.