They range from a sickly economy in which more than a quarter of the workforce is jobless to entrenched crime and corruption and land ownership that remains overwhelmingly in the hands of whites.
Many solutions will require him to inch his way across the high wire, balancing leftwing calls for radical change with demands by investors for caution.
In his acceptance speech to lawmakers on Wednesday, Ramaphosa vowed his government was all "about change, and you are going to see the change."
"We have been given this responsibility on an overriding basis to revive our economy, to create jobs, to not only bring hope to the masses of our people, to actualise that hope and make sure that indeed their aspirations are met."
Ramaphosa's first test as he starts his new five-year term will be choosing a cabinet -- a task beset by rival factions within the ANC.
He is expected to name his new cabinet within days after his inauguration, but his choice of vice president hangs in the balance after his deputy David Mabuza said Wednesday he would defer taking his seat as a lawmaker.
An ANC integrity commission report has alleged Mabuza -- the party's No. 2 -- "prejudiced the integrity of the ANC and brought the organisation into disrepute".
Ramaphosa first took power last year when the ANC forced Jacob Zuma to resign after nine years in office, and vowed to root out corruption.
"The clean-up is ongoing, the cabinet will be broadly clean and meet some notional standard or threshold the market is looking for," predicted Peter Attard Montalto of the British-based advisory service Intellidex.
Breaking with tradition Ramaphosa's swearing-in ceremony has been moved from the amphitheatre of the Union Buildings -- the seat of government, where Nelson Mandela was inaugurated as the country's first black president in 1994.
All other leaders after Mandela have taken their oaths at the Union Buildings, whose grounds can accommodate only up to 4,500 people.
But this year the event has been moved to the 52,000-seater Loftus Versfeld rugby stadium, a move organisers said is more inclusive and will allow more people to witness the event.
More than 2,500 police are being deployed for security, while a battalion of soldiers will be inside the stadium to perform ceremonial parades.
The opposition Democratic Alliance (DA) has castigated the government for what it called "wasteful" expenditure of 120 million rand ($8.3 million) for the ceremony.
"It is no secret that the South African economy is in dire straits," said a senior DA lawmaker, John Steenhuisen.
Watch: South Africa President Ramaphosa celebrates election victory