Muhyiddin's grip on power had been precarious since coming to power in March 2020, but he lost his thin majority this month after lawmakers from a key ally withdrew support.
Here is a timeline of the rise and fall of Malaysia's eighth prime minister.
Feb 24, 2020
Prime Minister Mahathir Mohamad resigns as infighting causes the collapse of his coalition and the party led by Mahathir and Muhyiddin withdraws.
King Al-Sultan Abdullah re-appoints Mahathir as interim leader.
Feb 29, 2020
After meeting lawmakers, the king names Muhyiddin prime minister, assessing that he may have majority support in parliament.
March 1, 2020
Muhyiddin is sworn in as prime minister.
May 13, 2020
Parliament's speaker delays a confidence vote on Muhyiddin's leadership brought by Mahathir, citing a need to focus on the Covid-19 pandemic.
Oct 13, 2020
Opposition leader Anwar Ibrahim meets the king to prove he has support to form a government. The palace says Anwar did not name lawmakers supporting him.
Oct 23-26, 2020
Muhyiddin asks the king to declare a state of emergency to rein in the coronavirus. Anwar calls it a ploy to cling to power. The king rejects Muhyiddin's request.
Nov 26, 2020
Muhyiddin wins parliamentary approval for his 2021 budget, seen as the first real test in parliament.
Jan 12, 2021
The king declares a state of emergency until Aug 1 over rising Covid-19 infections. Parliament is suspended, allowing Muhyiddin to continue unopposed.
Opposition decries the move as a bid to retain control.
A key ally, the United Malays National Organisation (UMNO), which is the biggest party in the ruling coalition, says it will not cooperate with Muhyiddin's alliance in the next election.
The king meets leaders of political parties as public anger grows over the government's handling of the coronavirus crisis after Malaysia enters a nationwide lockdown in June.
The king calls for parliament to reconvene as soon as possible to allow debate of emergency ordinances and a coronavirus recovery plan.
No need to extend the emergency beyond Aug 1, says the nine-member conference of rulers, which includes the king.
Muhyiddin names UMNO lawmaker and defence minister Ismail Sabri Yaakob as his deputy to shore up support.
UMNO withdraws support and calls on Muhyiddin to resign for mishandling the pandemic.
Muhyiddin calls a special session of parliament at the king's request. Law Minister Takiyuddin Hassan tells parliament the government will not ask the king to extend the state of emergency and says emergency ordinances revoked.
In a rare public rebuke, the palace says the revocation of emergency ordinances was done without the king's consent and runs counter to the constitution and the law.
Muhyiddin agrees to consider debating emergency laws in parliament, easing a standoff with the monarchy.
Muhyiddin insists he retains majority support and says will prove it in a confidence vote when parliament reconvenes in September.
Muhyiddin acknowledges he does not have a majority. He urges opposition lawmakers back him in a confidence vote in exchange for reforms and says elections will be held by July 2022, depending on the pandemic.
Opposition parties and UMNO reject the offer.
Muhyiddin tenders his resignation to the king who asks him to stay on as interim premier until a new appointment is made.