Since 1999, Klus has been engaged in not only the non-profit sector with the aim to empower civic[1] and studied participation in public affairs, but also educational[2] and urban environment[3] improving activities.

[6] In the 2010 Slovak political reform referendum, Klus achieved 1056 votes in Banská Bystrica's 7th precinct and became the first substitute representative, one place ahead of Marian Kotleba.

[12] Klus ran for 2016 Slovak parliamentary election as a candidate of Freedom and Solidarity, receiving 21,513 votes of preference which ensured him the seat of Member of the National Council of Slovakia.

Based on pre-election polls, Klus dropped out of the race in favor of Ján Lunter on 3 October,[16] who defeated Marian Kotleba.

From the parliamentary elections in 2020 until the ministerial resignations of SaS in Cabinet of Eduard Heger, Klus served as the State Secretary of the Ministry of Foreign and European Affairs.