The Cairn Group-owned site has been renamed as the Hotel Indigo Edinburgh Princes Street after a revamp of its 64 bedrooms, lobby and Juniper cocktail bar.
It comes after Cairn Group refinanced £101m in May with plans to expand and refurbish its portfolio of over 60 hotels, bars and restaurants.
The development has also created 12 new jobs.
Naveen Handa, director at Cairn Group, said: “Edinburgh has such a vibrancy about it and is the perfect place to house a Hotel Indigo branded property.
“As a result of the conversion and significant investment, the hotel has had its offering for guests enhanced, as well as bringing new jobs to the city and creating opportunities for staff progression and development.”
In November Cairn Group acquired five former Hotel Collection properties across the UK for £75m.