Three seasoned ministers will take a bird's-eye view of government and oversee issues involving multiple ministries.
Deputy Prime Minister Teo Chee Hean will oversee national security, while Deputy Prime Minister Tharman Shanmugaratnam will coordinate economic and social policies.
Rounding out the group is new Transport Minister Khaw Boon Wan, who will tie urban planning and infrastructure together.
Such "coordinating ministers", as Prime Minister Lee Hsien Loong termed them, are needed as Singapore faces complex issues that demand a more coherent response from the Government as a whole. They can also mentor younger, newer ministers, he added at the press conference in the Istana where he unveiled the new Cabinet.
"With a coordinating minister overseeing them, I can take the chance on a new person and let him find his feet and master the job. And we can be sure that they will work out," he said.
Mr Tharman's successor as Finance Minister is Mr Heng Swee Keat, who entered politics in 2011 and was the Education Minister.
Mr Heng's batchmate, outgoing Minister for Culture, Community and Youth Lawrence Wong, succeeds Mr Khaw as National Development Minister.
Mr Teo and Mr Tharman will relinquish their posts as Home Affairs Minister and Finance Minister respectively to focus full-time on their roles as coordinating ministers.
Explaining why he made the appointments, Mr Lee said more and more issues cut across ministries and departments. Population, for one, is influenced not only by economic incentives but also social and housing policies.
Further illustrating his point, Mr Lee said infrastructure includes roads and rail lines, houses, schools and even information technology infrastructure - involving at least four ministries.
"Not easy to coordinate, but it all has to come together. I cannot have one ministry for each of these cross-cutting things. And even if I did, they would all have to link up with one another,'' he said.
This is where coordinating ministers can come in and "help to bring the pieces together", he added.
He also said the introduction of coordinating ministers is not new.
For instance, Britain has secretaries of state. Indonesia has "menko", short for "menteri koordinator" or "coordinating minister" in Bahasa Indonesia. Multiple ministers work under a menko.
"We are going some way in that direction," Mr Lee said.
He added that he had not designated which ministers report to which coordinating minister, as they may have to report to more than one.
Elaborating on the need for such ministers, Mr Khaw said there has always been coordination among government officials.
"But what is critical now is that we inject this political leadership, to make sure political considerations are fully factored in too."
Mr Teo, when asked about his priorities as coordinating minister, said he wanted to focus on tackling new challenges of terrorism in the light of the Islamic State in Iraq and Syria militant group's activities.
As for Mr Tharman, he noted that Singapore had started on economic and social programmes, such as economic restructuring, the SkillsFuture drive to upgrade workers' skills, and strengthening the social safety net.
The choices ahead were not simple, he said. "We have to think very hard about what can we afford, how we provide the right incentives, what shake-ups can we accept in the economy."
He added: "I am not going to be peering over the shoulders of ministers, but it's continual consultation, advice, before we actually come to an agreement in (the) Cabinet."