Donal Hassett, 57, was accused of acting as the property fixer using fake paperwork to rent four homes which were later turned into cannabis factories.
He was convicted at Bristol Crown Court on Wednesday of conspiring to produce cannabis.
The prosecution described their drugs operation as an "organised, sophisticated drugs syndicate".
Cannabis was produced between January 2015 and March 2016 in four properties across the West Country, the court heard.
Hassett, of Southdown Road, Bath, was suspended from the Conservative Party when he was charged. He is currently an independent councillor.
Conservative leader Tim Warren said in a statement on Wednesday that "the party, and he personally, felt very let down by Donal Hassett".
A council spokesman said: "The council takes this matter extremely seriously.
"We expect the highest standards from all our members and Cllr Hassett's behaviour falls far short of this."
Hassett was remanded in custody until sentencing.
Six others, five men and woman are due to be sentenced for their part in the drugs ring.

A spokesperson for the Co-op said two of the chocolate figures had been found to contain a small button-cell battery.
"The health and safety of our customers is our top priority," said the spokesperson, adding that the Co-op was investigating and the police and Food Standards Agency were being notified.
No other products are affected.
The Co-op chocolates that had been subject to tampering were bought at two locations, one in Suffolk and one in Essex.
It is thought that the tampering took place after the Santas left the factory.
Surgeons recently warned that button batteries pose a potentially deadly risk to young children.
If accidentally swallowed, the small, round batteries can get lodged in the oesophagus and burn a hole through its lining.
The most serious cases are associated with Lithium button batteries larger than 20mm (the size of a 10 pence piece) which can cause severe injury within two hours.
London's Great Ormond Street Hospital said in September that it had seen a big increase in cases in the past year.
The Co-op said customers with one of these products should not eat it, but call the company's customer relations team for a full refund.
Anyone who is concerned should call Freephone 0800 0686 727.

Dionisio Vilca set off on his search, protesting that the authorities had abandoned efforts to find his police officer son Cesar.
Cesar Vilca had been missing for 20 days, after his unit came under attack by rebels in the southern Cusco region.
Another officer, Luis Astuquillca, was shot in the leg but walked for 17 days through the rainforest to safety.
With the help of two local people who had spotted Cesar's body, Mr Vilca set off to recover his remains.
Travelling in a pick-up truck, the group reached the spot and took the police officer's corpse back to the nearest community.
Mr Vilca had complained that the authorities had wound down their efforts to locate Cesar.
But the interior ministry noted that there had been "an intense and prolonged search"  that had cost the lives of three members of the security forces.
Cesar Vilca and his unit were deployed on 12 April to search for a group of 36 gas workers abducted by Shining Path rebels.
They came under fire from the guerrillas and four officers were killed.
The hostages were released by their captors six days after being abducted in a remote region close to the Ene-Apurimac valley - one of the last strongholds of the Shining Path.
The Shining Path posed a major challenge to the Peruvian state in the 1980s and early 1990s, but is now reduced to small gangs involved in cocaine trafficking.
A Bath councillor has been found guilty of being involved in a cannabis drugs ring.
[NEXT_CONCEPT]
The Co-op grocery chain has announced a nationwide recall of 165,000 hollow milk chocolate Santa figures after two alleged tampering incidents.
[NEXT_CONCEPT]
A Peruvian father has recovered the body of his son, after embarking on a nine-hour journey through the jungle.