"I want to do well, because when a president does well the country does well, and I want to do well for this country," he told reporters after Congress formally ratified the results.
Growing up in the presidential palace in Manila, Marcos Jr wanted to be an astronaut before he followed in his father's footsteps into politics.
He served as vice governor and twice as governor of the family's northern stronghold of Ilocos Norte province, and also had stints in the House of Representatives and the Senate.
His 92-year-old mother, Imelda, said she had dreamed of him becoming the country's leader.
Marcos Jr's links to his father, whose rule was marked by the bloody repression of the martial law years, have made him one of the nation's most polarizing politicians.
He has benefited from a deluge of misinformation on social media targeting a largely young electorate with no memory of the corruption, killings, and other abuses committed during the elder Marcos's 20-year rule.
His campaign was bolstered by teaming up with Sara Duterte -- who won even more votes than Marcos to easily secure the vice presidency -- as well as the backing of other political elites.
Marcos Jr and Duterte's shared history as the offspring of authoritarian leaders has alarmed rights groups and many in the clergy, who fear they will use their victory to entrench themselves in power.