It follows reports that President Trump was outraged by comments made by Mulvaney during the Ukraine corruption saga.
The allegations of abuse of power over the Ukraine incident led to impeachment proceedings against President Trump.
Mulvaney's departure has been on the cards for the last few weeks.
Mr Mulvaney is to become US special envoy to Northern Ireland, while North Carolina lawmaker Mark Meadows has been appointed to take over his former position.
US Epstein files release highlights Clinton, makes scant reference to Trump
The US Justice Department released thousands of heavily redacted documents related to the late financier and convicted offender Jeffrey Epstein on Friday that extensively featured Democratic former President Bill Clinton.
Bangladesh holds state funeral for slain youth leader amid tight security
Tens of thousands of Bangladeshi mourners, including the country's interim government leader, attended the funeral on Saturday of a slain youth leader and election candidate amid tight security.
US hits ISIS in Syria with large retaliatory strikes, officials say
The US military launched large-scale strikes against dozens of IS targets in Syria on Friday in retaliation for an attack on American personnel, US officials said.
Pakistan court hands Imran Khan, wife 17-year jail terms in another graft case
A Pakistani court on Saturday sentenced former Prime Minister Imran Khan and his wife Bushra Bibi to 17 years in prison each in a corruption case involving the under-priced purchase of luxury state gifts, the court and Khan's lawyers said.
Latest With Hit
Akhil Kavalayoor live on Radio Active
Latest With Hit
Watch Dona & Jean as they grove to SakkathaGavle !
Latest With Hit
Ted X speaker, AI trainer Raul John Aju giving us AI lessons.
