A royal commission-style inquiry is probing the ASX-listed company over allegations it enabled suspected money laundering, organised crime, fraud and foreign interference at its venues, including The Star Sydney.
John O'Neill, who tendered his resignation as chairman late last week, told the inquiry on Monday that cleansing was needed after parts of the company's business went "very badly wrong".
"That cathartic moment requires as much cleansing as possible, and that's what we've attempted to do," said Mr O'Neill, who is also stepping down from the board.
The inquiry is investigating Star's suitability to run its Sydney casino.
Many of Star's top brass, including managing director and chief executive Matt Bekier, chief financial officer Harry Theodore, chief casino officer Greg Hawkins, and chief legal and risk officer Paula Martin have left in recent months.
Further high-level resignations are anticipated, the inquiry heard.
Asked whether the resignations represented an extraordinary situation, Mr O'Neill said the circumstances required extraordinary action.
He said the board did its best to model leadership.
"We attempted to the best of our ability to get the message down to the line as what's acceptable and what's unacceptable," he said.
He denied the board was complacent about problems at the company, attributing issues to a subculture in the international rebate and VIP divisions, especially related to junkets, China Union Pay (CUP) and offshore bank accounts.
The inquiry was previously told that in 2019, China Union – a Chinese financial services company – became concerned that its cards were being used at Star venues to pay for large "suspicious" gambling transactions in breach of its rules.
Mr O'Neill said bad habits went undetected in what was essentially a duopoly in the industry, noting the interchange of people between Star and rival Crown Resorts.
"You're only as good as the people who work for you," he said.
Quizzed about whether there were ethical failures by senior casino managers, Mr O'Neill conceded there had been examples of untruthfulness, errors of judgement, lack of oversight and in some cases lack of ethical considerations.
He conceded that Star had not been sufficiently attentive to its anti-money laundering and counter-terrorism financing obligations.
Star announced on Monday that Ben Heap will assume the role of interim chairman, while Geoff Hogg will become acting chief executive.
Earlier on Monday, Star director Richard Sheppard blamed some of the casino operator's failings on not refreshing management.
"The management had been doing things a certain way," Mr Sheppard said.
"There wasn't fresh eyes and a fresh approach."
Mr Sheppard urged more diversity on Star's board, including adding someone with a legal enforcement background, not a business background.
The inquiry was told several senior casino managers hid information from the board.
"We possibly didn't ask enough questions, but I can absolutely assure you that the board asked lots of questions".
The inquiry continues on Tuesday.