The election took place on Sunday, the fourth day of the party congress, held every five years, according to the state news agency KCNA.
During the event, Central Committee members were also elected, and some party rules were modified, it said without providing details, Al Jazeera reported.
Kim has been North Korea’s supreme leader since the death of his father, Kim Jong Il, in 2011.
In 2019, North Korea’s legislature approved constitutional changes to make Kim’s power “monolithic” over all state affairs, formally establishing him as head of state.
During this year’s Workers’ Party Congress, Kim assessed the party’s last five years of work and outlined new strategies and goals for the next five-year period.
Speaking at the event’s opening session last week, Kim called the last five years a “proud period … in implementing the socialist cause of our own style”, while acknowledging challenges such as sanctions and “the global public health crisis”.
“Today, our Party is faced with heavy and urgent historic tasks of boosting economic construction and the people’s standard of living and transforming all realms of state and social life as early as possible,” the KCNA quote him as saying.
“This requires us to wage a more active and persistent struggle without allowing even a moment’s standstill or stagnation.”
Other high-level officials also delivered remarks at the Congress, including Minister of Foreign Affairs Choe Son Hui.
Kim stated during his opening address that North Korea had overcome its “worst difficulties” in the last five years, and was now entering a new stage of “optimism and confidence in the future”.
Ahead of the congress, Kim held a ceremony unveiling dozens of nuclear-capable rocket launchers, which he hailed as “wonderful” and “attractive”.