Novak is a loyal ally of Hungarian Prime Minister Viktor Orban.
Katalin Novák has been elected as Hungary's first female president.
She received 137 votes from MPs on Thursday, ahead of her opposition rival, economist Péter Róna, with 51.
Novák, 44, is a loyal supporter of populist Prime Minister Viktor Orbán and formerly served as Hungary's youth and family minister.
"So help me God," Novák said after winning the support of MPs, while also condemning Russia's invasion of Ukraine as "unacceptable".
She had been favourite to win the presidential vote, given that Orban's Fidesz party holds a large majority in the Hungarian parliament.
Novák has defended Hungary's traditional family values and delivered a passionate speech to MPs before the vote.
Her appointment comes less than a month before Hungary's parliamentary elections, which are expected to be close.
The six opposition parties have formed an unprecedented alliance in the hope of toppling Fidesz and Orban, who has been criticised for attacking the rule of law since 2010.
Opposition leader Peter Marki-Zay had said that Novak was "unfit" for the post of president because of her closeness to the Hungarian PM.
Her predecessor Janos Ader was himself a co-founder of Fidesz and had held the presidency since 2012.
Novák will hold a five-year term as Hungary's president, where she has the power to temporarily block laws and call referendums.