In 2005, Castro graduated in Law at Federal University of Rio de Janeiro (UFRJ).

In his office, led the organization of political projects in the defense of life, of children and teenagers in situation of risk, of people with disabilities and fight against drugs.

On 6 August 2018, the Social Christian Party (PSC) confirmed that City Councillor Cláudio Castro would be a candidate for Vice Governor of Rio de Janeiro along with federal judge Wilson Witzel,[5] and that the party would not form any coalition.

[6] With 59.87% (4,675,355) of the valid votes, Witzel and Castro were elected on 28 October 2018 for a four-year term, which began on 1 January 2019.

[7][8] Castro was sworn in as Governor of Rio de Janeiro, after Wilson Witzel's impeachment on May 1, 2021.