He was nicknamed "Gentleman of the Seas" for his kind and chivalrous treatment of defeated enemies and is held in high esteem by both Peruvians and Chileans.

The relationship between his parents was extramarital as his mother, María Luisa Seminario y del Castillo, was also married to Colombian captain Pío Díaz and they would have three legitimate children together: Roberto, Emilio and Balbina.

These voyages gave Grau the seagoing experience that was the foundation for his brilliant career as a nautical officer and the beginning of a love story with Carla Ortiz (unidentified French women).

He would be put in prison a year later, with a group of fellow officers for rejecting the idea of hiring a foreigner as supreme commander of the Peruvian navy, but was later released after a trial in which they were declared not guilty as their cause was proven worthy.

By 1 June 1874, he became the commanding officer of the Peruvian Navy's fleet as captain, and later became a member of the Congress of the Republic of Peru as an elected congressman in 1876 representing Paita.

[6] When the War of the Pacific between Chile against Bolivia and Peru began on 5 April 1879, Miguel Grau was aboard the Huáscar, as its captain and the Commander of the Navy.

In an impressive display of naval mastery, Capitán Grau played an important role by interdicting Chilean lines of communication and supply, damaging, capturing or destroying several enemy vessels, and bombarding port installations.

At the Battle of Iquique, after Huáscar sank the Chilean corvette Esmeralda by ramming her, Grau ordered the rescue of the surviving crew from the waters.

His final resting place lies at the Escuela Militar Naval del Peru, in El Callao in an underground mausoleum.

He posthumously received the rank of Gran Almirante del Perú (Grand Admiral of Peru) in 1967 by order of the Peruvian Congress.

[citation needed] In December 2019, a bust of Grau was donated by the Peruvian Navy to the United Kingdom in Wirral, in tribute to the historic naval links between Peru and Birkenhead.

An example includes the modern-style monument in Piura, remodeled in 2019[12] featuring symbolic elements of strength and valor, and the bronze statue in Callao inaugurated by President Nicolás de Piérola in 1897.

The hyper-realistic statue unveiled at the Naval Museum of Callao in 2021, using artificial intelligence to achieve detailed likeness, stands as a testament to his enduring legacy.