In his place, Johnson appointed former Covid vaccine minister Nadhim Zahawi - following his promising execution of the vaccine roll out across the country.
Williamson has faced increasing pressure to stand down, from backbenchers, opposition and the electorate, as the English school curriculum remains uncertain in the year ahead.
So, who is Zahawi and what is his record as an MP? This is what you need to know about the new Education Secretary.
Who is Nadhim Zahawi?
Zahawi has been the MP for Stratford-on-Avon since 2010, though he grew up in Sussex and attended private school, the first being in Roehampton.
Born in June 1967 in Baghdad, Iraq, to Iraqi Kurdish parents, Zahawi immigrated to Britain with his family when he was nine-years-old.
In 2000, he co-founded internet political market research company YouGov and remained the chief executive until February 2010. He was elected to the UK parliament for the Conservative party in May 2010.
Until 2018, he remained the chief strategy officer for Gulf Keystone Petrolium, which paid him up to £30,000 a month.
He is married and has three children, the family are keen horse riders and have a stable and riding school at their Warwickshire home.
Where was Nadhim Zahawi educated?
Zahawi was firstly educated at comprehensive Holland Park before moving to private Ibstock Place School in Roehampton.
He then attended King’s College School, an independent school in Wimbledon, before achieving a BSc in Chemical Engineering at University College London.
The majority of Education Secretaries have been privately educated.
What other ministerial positions has he held?
Zahawi was first elected as a politician in 1994, as a councillor in Putney, London. He was re-elected to serve a total of three terms before stepping down in 2006.
Since being elected to parliament in 2010, he has served as Minister for Children and Families under former Prime Minister Teresa May and was subsequently appointed Johnson’s Parliamentary Under-Secretary of State for Business and Industry and also spent a brief time as a junior minister for Education.
In 2020, he was given the additional role of Parliamentary Under-Secretary of State for COVID-19 Vaccine Deployment.
What are his values and voting record?
In Education, he has voted for increasing the maximum amount charged in England for undergraduate degrees to £9,000 per year, as well as voting to end financial support for disadvantaged 16-19 year olds in training and further education.
He voted to leave the European Union, arguing Britain needed to take back control of its borders and has generally voted against a right to remain for EU nationals already in living in the UK and increased EU migration.
He voted down an amendment to force private landlords to make their leased properties “fit for human habitation,” he has a registered interest in private property as he generates income from leasing properties.
He was accused of misrepresenting data during a debate on whether to extend free school meals into the school holidays - he argued parents preferred to pay £1 or £2 for their child’s school meals.
In February 2021, he insisted that he would not introduce mandatory Covid vaccine passports for international travel, he has since announced that from September, covid passports will be required to access some events and venues in the UK.
Zahawi has also generally voted down policies which would seek to prevent further climate change - he has previously been employed in the oil sector.
He has consistently voted against stopping the inflation of rail ticket prices, while voting in favour of increasing the price of plane tickets.
He has almost always voted against giving increased power to local councils and devolved parliaments.
Why has he replaced Gavin Williamson?
Williamson’s most recent calls to resign came just one week ago, when he mixed up two sportsmen, Marcus Rashford and Maro Itoje.
Both had lobbied the government on issues affecting children’s education - free school meals and access to laptops for disadvantaged children being home-schooled during the pandemic.
However, this is only one of a series of mishaps he has endured throughout his period as Education Minister.
He argued a council in England could not shut early before Christmas last year - at the height of the Covid second wave - only to close schools one day after they returned in January.
Prior to this, thousands of children were marked down in their A level examinations in 2020 due to an algorithm which appeared to unfairly disadvantage pupils in poorer areas.
He claimed he only realised "over the weekend" that there were major flaws in students’ A-level grades.
At present, following two years of cancelled exams for secondary school pupils, schools are still unaware of whether exams will go ahead in 2022 or whether teachers will again assess their students based on in-class and homework.