Ramaphosa rolled out strict confinement measures on March 27, under which people were only allowed to leave their homes for groceries, pharmaceuticals and medical appointments.
Though infections rose to nearly 4,000 cases on Thursday and 75 deaths, the disease's spread has slowed during an initial three-week lockdown period that was later extended until April 30.
But authorities have struggled to keep people indoors -- particularly in overcrowded townships -- and many businesses feared they would not be able to recover from a prolonged shutdown.
"We have accordingly decided that beyond Thursday the 30th of April, we should begin a gradual and phased recovery," Ramaphosa said in a televised address.
"We will implement what we call a risk-adjusted strategy through which we take a deliberate and cautious approach to the easing of current lockdown restrictions."
A $26 billion relief package was announced earlier this week to stimulate the economy and cushion vulnerable people during the coronavirus pandemic.
"While a nationwide lockdown is probably the most effective means to contain the spread of the virus, it cannot be sustained indefinitely," Ramaphosa said, adding that "clear evidence" showed the restrictions had been working.
"Our people need to eat, they need to earn a living. Companies need to produce and trade."
While South Africans are still encouraged to remain home, some businesses will be able to resume operations "under specific conditions" and in a "phased manner" as of next month.
Borders are to stay shut and a ban on alcohol sales remains in place.
'Tough battle' ahead
But people will be allowed to purchase cigarettes and exercise outdoors in "strict public health conditions".
The gradual lifting of confinement measures will be compensated by investment in public health.
Ramaphosa called on all citizens to start wearing face masks outdoors and pledged 20 million rand (around $1 million) for hospital beds, medicine and equipment to tackle an expected "peak of infections".
South Africa has the continent's highest number of coronavirus cases, with 3,953 infections announced on Thursday and 75 deaths.
That increase was the highest single-day jump recorded so far, and Health Minister Zweli Mkhize warned South Africa still had a "tough battle to fight".
Meanwhile, the main opposition Democratic Alliance (DA) party hailed Ramaphosa's announcement as a "smart lockdown model".
"What is crucial is that any such a phased lifting of lockdown restrictions is accompanied by both a massive increase in testing... and reliable data," added the DA in a statement.
Some 28,000 community health workers have been deployed across South Africa to screen and test its 57 million inhabitants.
Government also plans to send more than 73,000 extra troops to enforce coronavirus regulations.
Political analyst Daniel Silke warned it would be more difficult to lift the lockdown than it was to impose it.
"It's not just being unsure of exactly how to tackle this in terms of the regulations," Silke told AFP.
"It is unsure what effect it will have on the health of South Africans."