[3] He wrote and directed the anti-imperialist play Nápun, Ngéni at Búkas (Kahapon, Ngayon at Bukas; Yesterday, Today and Tomorrow), which led to his arrest in 1903.

In Tondo, he met Andres Bonifacio, one of the founders of Katipunan and eventual leader of the Philippine revolution against Spain.

He accompanied Bonifacio in their search for a secret headquarters in the mountains of Morong province (now Rizal) in preparation for the start of the Philippine Revolution.

[6] When Spain ceded the Philippines to the United States, Tolentino formed Junta de Amigos, a secret organization composed of former Katipuneros to fight for independence from the Americans.

Tolentino also founded the first worker's cooperative in the Philippines, Samahang Hanapbuhay ng Mahihirap, as well as El Parnaso Filipino, a school for the promotion of Tagalog literature.