Edmund Ellwood, known as Eddy Ellwood, 58, was convicted on Friday, April 8, of four offences relating to the use of Xtreme Fitness on the Longhill industrial estate early last year.
At the time England was under strict Tier 4 restrictions which required commercial gyms to close.
The professional bodybuilder was fined £30,000 for the breaches and ordered to pay the prosecution’s costs of £25,507 plus a £181 court surcharge.
District Judge Marie Mallon said: “This was a deliberate and flagrant disregard of the law.”
But in a defiant speech to the court, Ellwood insisted he had not done anything wrong and would be appealing.
During a trial at Teesside Magistrates’ Court, he said he had used his gym as the base for a support group for people whose mental health was suffering due to lockdown and wished to protest against the Government’s restrictions.
He said he would not deny people the use of equipment if it helped them to feel good.
Hartlepool Borough Council, which prosecuted Ellwood, described the protest argument as a “sham” and the judge agreed saying there was “overwhelming evidence” to support that.
She said: “To whom were they protesting? How were they making their presence known?”
Police and a council officer said they saw people using the gym when they visited it in January and February last year.
On one occasion, a number of gym-goers were seen to run away and hide behind a vehicle.
District Judge Mallon said: “There was ample evidence of people using the gym equipment.
"They were wearing gym clothing [and] carrying gym kit.”
Giving evidence in the trial, Ellwood said he wanted to help people due to concerns over suicide among gym users during lockdown.
After being sentenced he called the case a sham and said in a statement: “There’s nothing shameful about putting another man or woman’s needs before your own.
"I was there to attend to those people’s suffering and in need of my help.
"I have served humanity by caring, I haven’t done anything wrong.”
He added: “I will be appealing this unfair decision.”