Business development manager Tim Mason is leading the project for the 14-centre group.
The shop has a 2,000sqm indoor retail area, 112-cover coffee shop and plant area with cafe 80 seats.
Concessions include Cotton Traders and a Pavers shoe shop as well as Oasis Windows, Neptune Spas and Fishy Business aquatics.
Turnover is expected to rise by 40 per cent to £2.1m in the first year.
Hillier has owned the site form 10 years and demolished the centre last year to build a new one. Architect was Plum, structures came from Newspan and groundwork was by Seasons Landscapes.
Mercia Interiors are shop fitting and Mike Hills is doing plant area benching.
Mason said: "If this makes a big difference to turnover at Eastbourne this high-quality retail environment we'd look to do elsewhere."
The site was previously a nursery and garden centre for more than 60 years.