Ádám Hernádi was born in 1986 in Esztergom. His parents are well-known and respected doctors in the city. As a child, he attended József Attila Primary School in Esztergom and completed his secondary education at Dobó Katalin High School in Esztergom. He earned his university degree from the Corvinus University of Budapest and speaks English and German.

He gained his administrative leadership and development policy experience at the Ministry of Public Administration and Justice, where he worked in the communications department, and later at the Prime Minister’s Office, where he held a department head position. He then became head of department at the Deputy State Secretariat for Key Affairs. Later, he was appointed deputy chief of staff in the Prime Minister's Cabinet and subsequently served as chief of staff to the State Secretary leading the Prime Minister's Programme Office. Following this, he was appointed chief of staff to the CEO of the Hungarian Tourism Agency, where he participated in the planning and implementation of Hungary’s tourism and development policies. In May 2019, he was appointed ministerial commissioner responsible for the tourism development of Esztergom. On October 13, 2019, he was elected mayor of the city for the first time.

During his first term as mayor, over the past five years, the municipality began addressing long-standing deficiencies to repay decades of debt to the city, aiming to restore Esztergom’s former glory as Hungary's first city. A significant milestone occurred in 2022 when the National Assembly voted on March 10th to restore Esztergom’s status as a county-level city, effective from May 1, 2022.

On June 9, 2024, he was re-elected as mayor with 70.33% (8,418 votes) support, the highest number of votes received by any mayor in Esztergom since the political transition.