The £55m scheme on Rhyl seafront by the Scarborough Development Group includes a 62-bedroom hotel, a supermarket, pub, petrol station and other retail units.
Councillors have given outline planning permission for the plan which the firm says could create 350 full-time jobs.
The Ocean Beach funfair, which opened in the 1890s, was bulldozed in 2007 and the site has been derelict ever since.
The new plan replaces a larger £85m development proposed by the Modus Group.
That scheme failed to materialise after the company went into administration.
Proposals in the original scheme for new homes and offices have been dropped from the latest plan and the proposed supermarket has been reduced in size.
Councillors say they hope there will be no further delays in transforming the site which has been described as "resembling a bomb site".
Vale of Clwyd MP Chris Ruane said: "It goes without saying that this site has taken far too long to be developed.
"There have been far too many false dawns and delays in developing what should be a prime site, not just in Rhyl, but in the central part of north Wales.
"Millions of pounds have been spent improving the harbour area but the opposite side of the road detracts from that.
"It is about time that development does take place and this should happen sooner rather than later.
"But - in retail terms - it does need to be done to complement the stores which are already available in the town centre."
A scaled-down plan to redevelop a former fairground in Denbighshire has been given the go-ahead by planners.