He ranked first in the list of candidates for deputies for the National List of the Vision with Values (VIVA) party in the
2019 legislative elections. He was elected as a deputy and took office on January 14, 2020 as part of the
IX Legislature of Guatemala. In mid-2023, it became known that Castillo, in his capacity as the party's general secretary, made an alliance with former Guatemalan president
Alfonso Portillo for the
2023 Guatemalan general election. On February 11, 2023, Castillo was proclaimed as the presidential candidate of Visión con Valores (VIVA) along with businessman Édgar Grisolia as the vice-presidential candidate. He was officially registered before the
Supreme Electoral Tribunal on March 10, 2023. Castillo placed fourth place in the first round receiving 9.44% of the vote. == References ==