A prominent member of the Peruvian Aprista Party, he was signaled in his youth as one of Víctor Raúl Haya de la Torre's main disciples, alongside future President of Peru, Alan García.

In his political career, he served in the Constituent Assembly of 1978–1979, which drafted the Constitution of 1979, in the now-abolished Chamber of Deputies, and finally as Peruvian Ambassador to Italy, appointed in Alan García's second presidency.

[1] Currently, Roca serves as Director of the Víctor Raúl Haya de la Torre House Museum.

In 1970, he was selected among the most talented young members of the party to the National Bureau of Conjunctions, under Víctor Raúl Haya de la Torre's leadership.

Upon Haya's death in August 1979, Roca took a prominent role in his wake, propelling him as one of the party's future congressional nominees for the 1980 election.

His followers accused the electoral tribunal of fraud in favor of Trelles, although Roca remained hopeful of the party's recovery in popularity.