He was jailed in 2018 after being extradited from the United States to face charges of forgery, false accounting and conspiracy to defraud.
The former chartered accountant was released from a low-security prison in Co Cavan at 10.30am this morning, the Irish Times reports.
He spent two years and eight months in an Irish prison along with six months in prison in the US before he was extradited.
Mr Drumm was sentenced for two specific offences, conspiracy to defraud and false accounting in relation to €7.2 billion in transactions during the banking crisis in 2008.
Judge Karen O’Connor said Mr Drumm engaged in “grossly reprehensible behaviour” and that his motivation to keep Anglo open, which his defence team argued should be a mitigating factor, was “irrelevant” and “does not provide any excuse for fraud and dishonesty”.