Chris Stewart, whose Edinburgh property company came unscathed through the crash to lead regeneration in the capital, has attracted a major new investor.

His Chris Stewart Group (CSG) announced that global investment adviser Proprium Capital had "agreed to make a significant minority investment of growth capital in CSG", though the terms were not disclosed.

Founded in 1996, CSG has a track record of executing complex transformational city-centre redevelopment projects, including its award-winning Advocate's Close development off Edinburgh's Royal Mile. It operates with a long-term objective of investing in high quality prime locations, drawing on its extensive relationships and experience.

The first deal concluded by the new partnership involves the funding of a 240-bed upmarket four-star hotel, for which CSG was awarded planning consent by Edinburgh Council 13 months ago. A dilapidated Georgian terrace dating back to 1789 at Baxter's Place below Calton Hill, the building has long awaited investment, and CSG was already committed to renovating the site as a hotel with public restaurant and bar.

The new financing deal enables the site purchase to go ahead. "The partnership with Proprium is a major breakthrough for our company," Mr Stewart said. "We have operated mainly in Scotland to date, focusing on giving heritage buildings a viable and dynamic future. The investment from Proprium and the working partnership that it brings now means we have significant firepower to transact more effectively on larger scale projects and address a broader market."

Mr Stewart, 39, a Dunfermline boy who left St Andrews University with no degree, built his company with backing from business angels, and latterly from Close Brothers. He managed to complete the sales of his major assets in the run-up to the crash raising £45 million, including the £13m sale to Apex Hotels of a Georgian block on Waterloo Place he had bought for £7.5m six months earlier from Aviva. That enabled CSG to pursue the development of the next-door block, in the teeth of the downturn, as a 96-bed hotel for Travelodge. Mr Stewart then got to work on his flagship project, Advocates Close at the edge of the Royal Mile. Since 2009, CSG has created a 208-room hotel, 29 apartments, three restaurants and office accommodation out of 11 tightly packed buildings, attracting hotel group Motel One to Scotland for the first time. The development's star attraction is a two-bedroom property which keen architectural historian Mr Stewart says is "possibly Edinburgh's oldest townhouse, which records show pre-dates 1490".

It has been restored in a year-long £45m project, to create an exclusive, £850 a night, serviced apartment with concierge, which opened for business last month.

Mr Stewart said: "This is an exciting time for the business."

Proprium is a spin-out of Morgan Stanley's real estate division and has more than $2 billion (£1.2bn) of assets under management globally, including substantial investments in the UK market.

Philipp Westermann, Proprium's head of Europe, said: "Chris Stewart Group is a fast-growing and entrepreneurial company with an outstanding track record. We are excited at the prospect of contributing to its future success through this capital injection, which will be used to invest in several attractive projects in Scotland and other parts of the UK."

Edinburgh-based Dickson Minto, along with Barclays and DLA Piper, were advisers on the transaction.