The cause of his death was not immediately disclosed. The emir was admitted to hospital late last month due to what the state news agency described at the time as an emergency health problem but said that he was in a stable condition, Reuters reported.
Crown Prince Sheikh Meshal al-Ahmad al-Sabah, 83, who has been Kuwait's de facto ruler since 2021, when the frail emir handed over most his duties, is the designated successor.
Sheikh Nawaf became emir in September 2020 following the death of his brother, Sheikh Sabah, who had ruled for more than a decade and shaped the state's foreign policy for over 50 years.
Sheikh Nawaf was seen by diplomats as a consensus builder even though his reign was marked by an intense standoff between the government and elected parliament, which had hindered key structural reforms in the oil rich Persian Gulf state. In recent months, consensus returned between the government and the parliament.
Kuwait, holder of the world's seventh-largest oil reserves, borders Saudi Arabia and Iraq, and lies across the Persian Gulf from Iran.
Since he took over in 2020, Sheikh Nawaf maintained a foreign policy that balanced ties with those neighbors, whilst domestically eight governments were formed under his rule.
Under Kuwait's constitution, the crown prince automatically becomes emir but assumes power only after taking an oath in parliament. The new emir has up to a year to name an heir.