Although news of the impending appointment broke several weeks ago, it was subject to federal Cabinet approval and only officially announced overnight.

Mitzevich last night posted a photograph of himself on Instagram with former NGA director Betty Churcher, saying he was honoured to be appointed to the new role in Canberra and “build on the extraordinary legacy”. He also thanked the Art Gallery of SA for “eight wonderful years”.

In a statement, the AGSA said gallery deputy director Mark Horton and assistant director, artistic programs Lisa Slade had been appointed acting co-directors until a new director was appointed, with the national recruitment process beginning this month.

Gallery board chair Tracey Whiting said Mitzevich had proven the “perfect choice” to help the gallery change direction and “re-invigorate public interest and public discourse around art in society”, with his achievements including growth in attendances to almost 800,000 a year.

“He leaves the gallery in a strong position, on the brink of a major capital project for the former Royal Adelaide Hospital site,” Whiting said.

“The board is excited by the prospect of appointing a director who can realise the vision of a new gallery, someone with relevant experience in managing a billion-dollar art collection, an immensely talented curatorial team and building an iconic institution with a global impact.”

Nick Mitzevich with Lisa Slade, who will share the role of acting co-director until a new appointment is made. Photo: Nat Rogers

Mitzevich conceived the plans for an internationally significant new contemporary gallery and sculpture park – dubbed the Adelaide Contemporary – for the old RAH site, winning support from former state premier Jay Weatherill. Ahead of the state election, then Opposition Leader and now Premier Steven Marshall announced his own plan to build Australia’s first national indigenous art and culture gallery on the old RAH site, although it was unclear how this would fit with Adelaide Contemporary.

AGSA has appointed arts administrator Michael Lynch, chair of the Adelaide Contemporary design competition, as special adviser to the Art Gallery Board to “assist with the delivery” of the new contemporary gallery.

Mitzevich will leave his current role at the end of this month and begins as director at the National Gallery in July, replacing retiring director Gerard Vaughan.

During his tenure in Adelaide he spearheaded a renewal in private giving and oversaw an acquisitions strategy that resulted in more than 4200 works of art enter the gallery collection – including a $4.5 million landscape by French Impressionist painter Camille Pissarro, described as the gallery’s most significant ever acquisition.