A nomination to admit Dame Julie as a honorary freewoman of the borough was submitted in June, and on Friday an extraordinary meeting of the council was held to bestow the honour - the first in seven years.
Dame Julie, who raised three children as a single mother, founded a security system manufacturing company in Rotherham and was made a CBE in 2002 for her services to industry.
Dame Julie, who grew up in Hillsbrorough and Stannington in Sheffield, moved to Cornwall aged 18 with just £45 to her name. After moving back to South Yorkshire almost ten years later, Dame Julie began working at a law firm.
In 1986, Dame Julie and her husband started their security system manufacturing business Pyronix - having sold her home to fund the start-up.
After becoming a single mother, she went on to turn Pyronix into a hugely successful business, which had a turn over of £25 million by the time she sold it in 2016.
She then went on to become the first female chair of the British Security Industry Association, and has racked up a number of impressive philanthropic roles - including helping to secure a £12m investment in Maltby Academy, and leading the restoration of Wentworth Woodhouse. where she is chair of trustees, having steered through its purchase for the nation by a preservation trust in 2017.
In an emotional speech, Dame Julie told councillors: “I’m very honoured that you have bestowed the honour of Freedom of the borough on me.
“Rotherham is a great town, its businesses are the best. It has fantastic culture, arts and heritage, and most of all, its people are simply the best.
“I was blessed with the people I employed, they made the difference to the business, and together we created wonderful products and services, and made a huge economic difference. I still get a sense of pride when I see my products installed all over the world.
“My proudest achievement after my children is a legacy for Rotherham, and that’s the work I do at Wentworth Woodhouse.
Coun Chris Read, leader of Rotherham Council added: “I want to add my congratulations to Julie Kenny on the awarding of this freedom of the borough award today, which reflects a marvellous life of of service.
“It’s seven years since we last awarded freedom of the borough. It is the highest honour that we can bestow on anyone with connections to our borough, and it’s right that we do that all the sparing we are for people who have done a truly exceptional things.
“The award should not be done for job well done or because someone has reached a particular level, they should be awarded because in individual has gone the extra mile in the contribution they’ve made to stand out, head and shoulders above others.
“And I can think of no one more deserving of the award, under those criteria than Julie - philanthropist, volunteer, entrepreneur, trailblazer.”