The confirmation comes a day after Vladimir Putin,
Kadyrov, 30, who had been Chechen prime minister, became acting president after last week's dismissal of Alu Alkhanov, who had increasingly criticised Kadyrov.
Security forces under the control of Kadyrov have been accused of human rights abuses by Russian and international rights organisations.
Kadyrov's nomination won 56 votes in the 58-member, two-chamber legislature, with two ballots ruled invalid.
Kadyrov follows in the footsteps of his father Akhmad Kadyrov, who was
Ahmed Kadyrov was assassinated in 2004, less than a year after he took office following a Kremlin-conducted election aimed at undermining the separatist rebel movement in
As prime minister, Ramzan Kadyrov led a federally-funded campaign to rebuild the region, left in ruins by two wars since 1994, in which Russian forces - and their local allies in the second war - fought separatist rebels.
Rebels and Russian soldiers still clash in the region where Russians are still targeted by roadside bombs and booby-traps.
Kadyrov has been at the heart of a Kremlin strategy to crush continued rebel resistance and establish order in the mostly Muslim region.
Kadyrov's accession to the presidency comes after prominent Russian rights groups boycotted a Moscow-organised human rights conference in
The rights groups said that attending the conference would lend Kadyrov's government undue legitimacy amid allegations of continued abuses in the republic.
Analysts say Putin has entrusted Kadyrov with power because he is seen as the only person who can keep
But his growing influence is also seen as a risk for the Kremlin; because some see his loyalty to