Prince Karim Husseini Aga Khan IV inherits the office of Imamat as the 49th Imam of Shia Imami Ismai'li worldwide, after the death of Sir Sultan Mahommed Shah Aga Khan III.

Shāh Karim al-Husayni (born 13 December 1936), known by the religious title Mawlana Hazar Imam by his Ismaili followers and elsewhere as Aga Khan IV, is the 49th and current Imam of Nizari Ismailis, a denomination within Shia Islam. He has held the position of imam and the title of Aga Khan since 11 July 1957, when, at the age of 20, he succeeded his grandfather, Sir Sultan Muhammad Shah Aga Khan III. The Aga Khan claims direct lineal descent from the Islamic prophet Muhammad through Muhammad's cousin and son-in-law, Ali, considered an imam in Shia Islam, and Ali's wife Fatima, Muhammad's daughter from his first marriage.

His grandfather, Aga Khan III, states in his memoirs that the Shias had a "need (for) Divine guidance" after the Prophet of Islam's death. This need of the Shias manifested in their belief system for the Institution of the Imamate. Thus, after the death of Prophet of Islam, the Shias established the Institute of the Imamate. According to the Aga Khan III as mentioned in his memoirs, he (the Aga Khan) has actual "Divine power, guidance, and leadership (authority)" The Institution of Imamate has continued to present day with the Aga Khan IV as the 49th Imam of the Ismaili Muslim Community. The Aga Khan is a business magnate with British and Portuguese citizenship, as well as a racehorse owner and breeder.Aga Khan's net worth has been estimated at $13.3 billion. Forbes describes the Aga Khan as one of the world's fifteen richest royals. Additionally he is unique among the richest royals as he does not rule over a geographic territory. The Aga Khan's personal wealth is kept entirely separate from the tithes (religious dues and contributions) given by the Ismailis. The tithes or religious dues of the Ismailis and all Ismaili Imamat assets are used exclusively for the needs, investments, and expenses of the Ismaili community - such as the construction and maintenance of Jamatkhanas, Ismaili community banks, cooperatives, loans,

and social programs, and funding for the Aga Khan Development Network operating budget. Among the goals the Aga Khan has said he works toward are the elimination of global poverty; the promotion and implementation of religious pluralism; the advancement of the status of women; and the honoring of Islamic art and architecture. He is the founder and chairman of the Aga Khan Development Network, one of the largest private development networks in the world. The organisation works toward improvement of the environment, health, education, architecture, culture, microfinance, rural development, disaster reduction, the promotion of private-sector enterprise and the revitalisation of historic cities.Since his ascension to the Imamate of the Nizari Ismailis in 1957, the Aga Khan has been involved in complex political and economic changes which have affected his followers, including the independence of African countries from colonial rule, the expulsion of Asians from Uganda, the independence of Central Asian countries such as Tajikistan from the former Soviet Union and the continuous turmoil in Afghanistan and Pakistan. Aga Khan IV became the first faith leader to address the Joint Session of the Parliament of Canada on 27 February 2014.