After a whirlwind buying spree snapping up pubs, hotels and bars, aspiring hospitality baron Jon Adgemis of rapidly expanding Public Hospitality Group has added hatted Sydney restaurant Alpha to his portfolio.

Fronted by chef Peter Conistis since its 2013 opening, rumblings of change at Alpha surfaced last year when its landlord and operator, the Hellenic Club, quietly invited a small posse of Sydney’s A-list Greek restaurateurs to pitch to operate the luxe Castlereagh Street restaurant.

Adgemis, a Greek-Australian, has ridden a few bumps expanding a burgeoning hospitality group that includes Oxford House and El Primo Sanchez in Paddington, and The Strand Hotel in Darlinghurst.

A recent partnership split with the Love Tilly Group led to a complex legal battle in which both parties made allegations of financial irregularities.

Adgemis’ proposal trumped his competitors for Alpha. The Hellenic Club has notified suppliers “that we have agreed terms with Alpha Brand Holdings Pty Limited (part of the Public Group) to take over the operation of Alpha and Beta”.

A Public spokesman says the group intends to preserve the venue’s “cherished” culinary heritage under the new management agreement. That includes retaining existing staff, with Conistis still engaged.

A Sydney restaurant veteran, Conistis made his mark with a string of chef’s hatted restaurants, from Cosmos and Eleni’s in Darlinghurst to Omega and Civic Dining in the city, before putting Alpha on the dining map with innovative dishes such as his moussaka of eggplant and sea urchin with taramasalata. The hospitality operation sprawls over several levels, including the award-winning Beta events space.

Conistis, who has been linked with an upcoming Greek mega-restaurant project at Brighton Le Sands, couldn’t be reached for comment. But he has a history of engaging with outside venues, including Ploos restaurant at Circular Quay, while maintaining his involvement at Alpha.