Zubeir Mister, 41, and Christopher Donaldson, 30, hired the men to work as kitchen staff in the Nice and Spicy fast food outlets in Morecambe, Lancaster, Preston, Kendal and Barrow.
But the curry shops did not pay the minimum wage, holiday pay or national insurance for the workers and the men would work long hours, up to seven days a week, a court heard.
Between January 2013 and March 2015, immigration officers raided Nice and Spicy branches 11 times - each time discovering a number of illegal workers in the kitchens.
In total 18 illegal workers were found - with several of the men being discovered on more than one occasion, working at different branches.
Jon Close, prosecuting, told the court: “This was a profitable and successful business. “However the staff were not paid well and even the managers earned little over the minimum wage.
Preston Crown Court heard the company hired the men to cope with the rapidly expanding business.
In 2012 there were branches in Lancaster and Morecambe but despite not having sufficient staff to cover those branches, new branches were opened in Barrow, Kendal and Preston, the court heard.
Mr Close said: “The solution was non-legit workers or to put it another way, illegal workers.
“People with the requisite skill set, who would either live on site or in a staff house and who would work long hours for low wages.
“The company would pay the illegal workers less than the minimum wage. They would not pay National Insurance. They would not pay tax. They would not pay holiday pay.
“They would work up to seven days a week, long hours for low rates of pay.”
On May 15 2015, immigration officers served a notice of potential liability on the company, warning them of a potential civil cost of £10,000 per worker that was employed illegally.
The court heard the notice was sent to Mister, who instructed Donaldson to ignore the letter. However Donaldson later replied and a high court writ was issued - which remains unpaid.
Despite the proceedings the company continued to employ illegal workers in the kitchens, providing accommodation, transport and food for them.
Janet Ironfield, defending Mister, said: “It is not said that the workers were housed in poor or squalid conditions.
“It [the offence] was in no way sophisticated. It is quite apparent that Mr Mister was doing the utmost to staff the business simply by speaking to past employees or word of mouth.
“This is not a case where there is any involvement with any person bringing people into the country.”
Judge Heather Lloyd, sentencing, said: “Zubeir Mister, your father set up the takeaway business in 1992 and it was called Nice and Spicy.
“It may have had different names but in reality it is the same business at the relevant times.
“It was effectively your business. You brought in others as partners and you Christopher Donaldson, were recruited in 2012 as a director and investor.
“I accept originally you had no experience of such business and it was your co-accused that organised all the paperwork and expansion of the business, including from time to time the expansion of the business premises, recruiting staff and paying bills.
“As time went on, you Donaldson, became familiar with the business and the way Mr Mister conducted the business and you began to take a more hands on approach.
“You, Mister, took a less hands on approach but it seems to me you were in overall control.
“Your overall desire was the expansion of the business and you could only achieve that and keep the existing premises open by continuing to use illegal workers.”
She jailed Mister, of Standen Park House, Lancaster, for 27 months and Donaldson, of Greenfinch Way, Heysham, for 22 months. The judge also made a Serious Crime Prevention Order lasting five years.