[12] On 31 August 2021, Karis was elected as the president of Estonia with a two thirds majority of 72 votes in the Riigikogu.

[2] The election received criticism and calls for electoral reform due to the absence of opposing candidates.

[14][15][16] In his acceptance speech Karis referenced the "turmoil that surrounded the presidential selection process" and called for changes of the system to be examined by the Riigikogu, such as using an enlarged electoral college, facilitating the nomination of candidates or even using direct election.

In December 2023 Karis refused to promulgate a law due to finding that the rules of proceedings were violated by the government by tying the bill to confidence vote.

[22] In July 2024 Karis did not proclaim the Vehicle Tax Act finding it to be unconstitutional in violating the principle of equal treatment in the part that deals with persons with disabilities.