At 40 years of age, Mr Desmond Lee will be the youngest full minister in the current Cabinet.
He will be Minister in the Prime Minister's Office from May 1, and continue in the Home Affairs and National Development ministries as Second Minister.
Mr Lee's political journey, which began in 2011 when he entered politics as a backbencher in Jurong GRC, has seen him rise rapidly.
In 2013, he was made Minister of State for National Development. He was promoted to Senior Minister of State in 2015, and took on the additional portfolio of Home Affairs.
Before Mr Lee, the youngest to be made full minister among the fourth-generation leadership was Mr Lawrence Wong, who was 41 when he was made Minister for Culture, Community and Youth.
When asked yesterday, Mr Lee - the son of former Cabinet minister Lee Yock Suan - said he was "humbled to be able to serve".
He would focus on three main areas in his new roles - transforming the built environment sector, partnering the community to conserve Singapore's national heritage, and tackling security threats such as terrorism, cybercrime and drugs.
A lawyer by training, Mr Lee helmed significant legislative changes recently. He fronted a Bill that grants the Government more regulatory powers over town councils last month, and argued for changes to the law to protect the reefs at Sisters' Islands Marine Park in February.
Dr Shawn Lum, president of Nature Society (Singapore), said Mr Lee has a unique ability to bring diverse groups of people together to have frank, open discussions. "He really takes the time to learn the issues from the stakeholder's point of view. He's a lawyer by training, not a biologist, but he made it a point to learn what the issues were, in order to understand us," he said, adding that Mr Lee would bring this unique skillset to a much wider group of people with this promotion.