Paciano Rizal was born to Francisco Engracio Rizal Mercado y Alejandro (1818–1897) and Teodora Morales Alonso y Quintos (1827–1911; whose family later changed their surname to "Realonda"), as the second of eleven children born to a wealthy family in the town of Calamba, Laguna.

In 1870, he accompanied his younger brother, Jose, to Biñan, Laguna in order to assist him in enrolling in the school of Sr. Justiniano Aquino Cruz. He also accompanied him, two years later, in Manila since Jose would already start his secondary education at Ateneo Municipal de Manila.^[1]

He grew up witnessing the abuses of the clergy and the Spanish colonial government. As a young student, together with Felipe Buencamino and Gregorio Sancianco, Paciano was a founding member of La Juventud Liberal, a reformist student organization that worked under the direction of the Comite de Reformadores, among whose leaders was Padre José Burgos. Among their tasks was to secretly distribute copies of the reformist paper, El Eco Filipino, while pretending to be purveyors of horse fodder (zacateros).

Burgos, who was Paciano's friend and teacher, was later implicated in the Cavite mutiny of 1872 and summarily executed at Bagumbayan, Manila.^[2]

Paciano joined and actively supported Propaganda Movement for social reforms, and supported the Movement's newspaper, Diariong Tagalog. An avid supporter of the movement, he did tasks such as collecting funds to finance the said organization and solicited money for the nationalist paper.

In January 1897, after his younger brother's execution, Paciano joined General Emilio Aguinaldo in Cavite. He was appointed brigadier general of the revolutionary forces, and was elected Secretary of Finance in the Departmental Government of Central Luzon.^[2]

During the Philippine–American War (1899–1913), he commanded the Filipino forces in Laguna. U.S. troops captured him in Laguna on 1900.^[2] He was released soon after, and he settled in the town of Los Baños, Laguna.

He lived a quiet life as a gentleman farmer, and died on April 13, 1930, at the age of 79 of tuberculosis.^[2][3]

• Portrayed by Ping Medina and Pen Medina in the 1998 film, Jose Rizal.
• Portrayed by Joonee Gamboa in the 1999 film, Bayaning 3rd World.
• Portrayed by Marco Alcaraz in the 2014 TV series, Ilustrado.
• Portrayed by Elijah Canlas in the 2023 film, GomBurZa.

• (Book) Paciano Rizal: a hero missing at the Luneta - a biography of José Rizal's Big Brother.