King Salman issued a royal decree appointing Saleh bin Fawzan al-Fawzan as the grand mufti.
The decision came after a recommendation by Crown Prince Mohammed bin Salman, the Saudi Press Agency reported.
Al-Fawzan, 90, was born in al-Qassim province and has been a member of the Council of Senior Scholars and the Permanent Committee for Scholarly Research and Ifta since 1992.
Ifta is the process of issuing a legal ruling, or fatwa, on a point of Islamic law.
The grand mufti in Muslim-dominated countries interprets Islamic laws and issues fatwas, which are religious edicts.
Al-Fawzan is well-known and has previously stirred controversy with his views.
He has supported the kingdom's decision to allow women to drive as a reflection of social development, despite previously stating that women driving can have harmful effects.
Like his predecessor, al-Fawzan had reservations about cinema and theatre, saying that these arts may contain elements that conflicts with Islamic values.
In 2017, Saudi Arabia began opening commercial movie theatres after a 35-year-old ban.
In the past decade, Crown Prince Mohammed began introducing slow-paced change like allowing foreign investments and loosening some social laws in the country that was known to follow a strict school of Islam.
In a 2017 report, Human Rights Watch said that in a recorded question and answer session, al-Fawzan said Sunnis should not call Shiites their brothers.
"They are not our brothers ... rather they are brothers of Satan ... Whoever says they are our brothers must repent," the report quoted him as saying.
Shiites are a minority believed to make up about 10 per cent of the predominantly Sunni population, and there were repeated reports of discrimination against Shiites.
Saudi Arabia's former mufti, Abdulaziz al-Sheikh, died last month after serving in the position for 26 years.
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