Mike Murray, senior development surveyor at St Modwen, said rejuvenation of the 468-acre site complex had now created 3,700 jobs, more than half the 6,500 lost when the car firm closed in April 2005.
But he said work could take another 20 years to complete to reach the ultimate target of 10,000 jobs on a site which was once the home of Europe's biggest car plant.
Mr Murray told the Post: "We are up to 3,700 jobs and 60 companies now. At the Innovation centre, which opened in 2007, we are heading up to 96 per cent capacity.
"The place is full with a mix of company expertise, with the likes of marine technology, developing apps etc.
"The success of Longbridge is about bringing jobs back for the future. If you look back to that horrible point of ten years ago, seeing 6,500 people walking out, the feeling was, 'What are we going to do with Europe's biggest car plant?'.
"We have now got people here who are in the music industry, education, IT, medical. Ten years on, the community is in a better place. There is a pride here in Longbridge again.
"There are 400 to 500 people at MG Motor UK, hundreds more at Sainsbury's, which trades well and is attracting people who would not be doing their shopping in Longbridge.
"The Costa Coffee downstairs is always full. Then there's Bournville College. We have moved our own head office here. It's a real mix, a balance between creating jobs and creating homes. We want to put the heart back into Longbridge.
"We have already built 300 houses and we have got another 1,200 to build. There will always be something happening here at Longbridge, but it could take 20 years.
"Last October, we had the Longbridge Light Festival and we had 5,500 people turn up. We are finding ten years on that the community are adopting the place, people are taking a positive interest in it. They see Longbridge for what it is now, not what it was in the past."
Mr Murray said the project had been achieved without significant public sector aid.
"Bearing in mind the recession, I would say that we have done really, really well," he added.
"We have not had government investment here on a big scale. It has all been done by the private sector and with the help of the planning authorities. We have never really stopped. Ten years on, we are still clearing the site. People can walk to work. They can grab a sandwich around here. They do not have to rely on driving.
"Last week, we got planning consent for 105,000 sq ft of offices. Some people still think of it as a site with rusty old padlocked gates and tumbleweed but this is the largest regeneration site in the Midlands.
"You have got all the engineering history here but nobody under the age of 14 knows the car plant. All they have is a sense of Longbridge, it is in the DNA of the area. We would like to achieve the target of 10,000 jobs - that would be job done.
"We have got Marks & Spencer opening at Christmas - another major retailer is putting significant investment into Birmingham. It is about a virtuous circle, getting jobs, homes and retail in.
"You can buy a house here, work here, do all your shopping here and, at the weekend, you have got the Lickey Hills to explore.
"Why would you want to go and work in the city centre? We have created an entire suburban community. There is no text book on it, no other examples of it."
Graeme Wintle, director of electronics design consultancy Bytesnap, said the firm's base at Longbridge Technology Park was "ideal".
He added: "The location here is a major factor. The motorway is not far away. The train station is ideal. Birmingham Airport is not far away.
"We looked at Birmingham city centre, Birmingham University, various private places and they were all limiting. Here we have a new building, good internet access, hotels, places to go and eat for lunch."