The Warrington-based group bought the Homes & Communities Agency's share in its long-standing joint venture.
The business was established by the government's Coalfields Task Force in 1999, and now has more than 750,000 sq ft of industrial and commercial space under management.
Among the properties acquired under the deal is Agecroft Network Centre, Swinton, which comprises 17 small industrial units to let from 775 sq ft to 2,650 sq ft.
John Downes, chief executive of Langree, said: "Our intention was to develop 500,000 sq ft of space but the concept and the product have proven so popular we've exceeded that by some margin.
"It was always the stated intention that we'd take full control once our development objectives had been met.
"The product will not change as it's popular, and provides the right type of quality accommodation and lease arrangements for SMEs in the current market."
Neil Mortimer, team leader of land and regeneration at HCA, said: "We are proud of the role Network Space has played in supporting our wider work with local partners to help regenerate former coalfield communities.
"Helping to restore jobs and promote business was always a priority for these areas and the vehicle has been successful in providing quality workspace."
Network Space owns 22 SME workspace estates and two business centres across the former coalfields of the North East, North West, Yorkshire and the Midlands.