By Rhiannon Hoyle

Northern Star Resources picked the head of Glencore's nickel and zinc industrial assets to be its next chief executive, opting for an outsider as it faces pressure from activist investor Elliott Investment Management for change.

Suresh Vadnagra--who, prior to Glencore, oversaw major projects and technical teams at gold company Newcrest Mining--will succeed CEO of 10 years Stuart Tonkin in October, Northern Star said.

The gold miner in May flagged Tonkin's intention to step down. Two weeks later, Elliott said it had built a stake in Northern Star valued at more than 1.0 billion Australian dollars, equivalent to US$689 million, and urged exhaustive operational and strategic reviews.

Northern Star, Australia's biggest gold miner, has been grappling with operational challenges, resulting in repeated downgrades to investor guidance. Its struggles mean it hasn't been able to fully capitalize on strength in the gold price, which reached a record high earlier this year.

Elliott said significant change is needed to earn back the trust of investors. It called for Northern Star to, among other things, prioritize hiring "a world-class external CEO with deep operational and turnaround experience to rectify the issues across the portfolio."

It had wanted the miner to add new directors to help with the CEO search.

On Thursday, Northern Star said Deputy Chairman Michael Ashforth will succeed Chairman Michael Chaney later this year. Chaney had previously advised shareholders this would be his last term.

Ashforth's "background in governance, transactions, capital allocation and leadership oversight positions him well to lead the board through Northern Star's next phase of growth," the miner said.

Northern Star said Vadnagra's appointment as CEO was the result of a comprehensive search that spanned internal and external candidates across the gold sector, diversified mining companies, base-metals producers and adjacent mining-related organizations.

"Suresh is an accomplished mining executive with the experience and capabilities to unlock the full potential of our assets and our people," said Chaney, the departing chair.

Shares in the company were 3.3% higher by midday in Sydney, although still down by more than 27% year to date.

Elliott said it looks forward to engaging with Northern Star's new leaders. Elliott, which manages about US$80 billion in assets, is one of Wall Street's most influential investors, known for pressuring companies to fire management, break apart and spin off businesses, all with the goal of increasing shareholder returns.

"The need for substantial board enhancement and a comprehensive strategic review has not diminished," Elliott said. The investor said it "remains committed to seeing the company realize its full potential."

Northern Star announced the appointments as it reported total gold sales of 433,000 troy ounces for the three months ended June. Annual gold sales exceeded 1.5 million ounces, in line with revised guidance, it said.

Write to Rhiannon Hoyle at rhiannon.hoyle@wsj.com