The Grade-II listed property received an investment of £26m from Starboard hotels and features 162 bedrooms.
There are also fitness facilities and a business suite, as well as a lobby fit with five stained glass deco panels.
Paul Callingham, executive chairman of Starboard, said: “This is a hugely significant moment, not only for our business and the team here at Starboard but also for the hotel sector in London and the West London community.
“It has been an ambitious project to redevelop the building and enhance the wonderful art deco features with a sympathetic restoration that reflects the heritage of both the building and its location.”
Situated on the A40, the hotel sits within the Mayor of London’s Old Oak and Park Royal regeneration scheme and offers views of Wembley Stadium and The Shard.
The project is Starboard’s first to take place in the capital, representing “an important milestone” for the business in this “challenging economic climate”.
Callingham added: “We are rightfully proud of the new Hampton by Hilton, London Park Royal which brings our portfolio to 21 hotels.”