Climbing the social and political ladder, he secured a job as personal secretary to Jerónimo Grimaldi, minister to the newly ascended king Carlos III.

As visitador del virreinato de Nueva España (inspector general for the Viceroyalty of New Spain) he exercised sweeping powers; the most in Spanish North America.

He boosted the mining industry further by reducing the price of mercury, a crown monopoly, which allowed a greater volume of silver ore to be refined.

Gálvez suppressed these by summary trials and sentences of life imprisonment, mainly in San Luis Potosí, Guanajuato and parts of Michoacán.

Overruling the Franciscans' appeal for clemency for miscreant soldiers, Gálvez punished most of them by assigning them to the upcoming expedition to Alta California — and discharged the rest from military service.

Gálvez worked with the Franciscan president of the Baja missions, Junípero Serra, in his projects to improve the lives of the natives, whom he called "the poor Israelites."

[11] Then, when a report arrived from the Spanish ambassador in Russia that Catherine the Great planned to establish settlements down the California coast towards Monterey, Gálvez trumpeted the Russian threat.

King Carlos gave the go-ahead, and Gálvez prepared a series of expeditions of soldiers, sailors, artisans, Christian Indians and missionaries to push north into unexplored upper California.

Gálvez established a naval base at San Blas and, in 1768–9, organized sea and land expeditions up the California coast to the projected Spanish outpost at the harbor named Monterrey (originally spelled with a double "r") by Sebastián Vizcaíno in 1603.

[13] On January 9, 1769, Gálvez, padre Serra and town dwellers gathered on the shore of La Paz to bless and send off the San Carlos, the expedition's flagship captained by Vicente Vila, a native of Andalusia.

[14] In his speech on the shore, Gálvez proclaimed that the ship's crew, including Franciscan friar Fernando Parrón, had the mission of planting the holy cross among the Indians at Monterey.

[17] While Gaspar de Portolá prepared his overland expedition to San Diego, Gálvez issued him strict instructions: ...To prevent difficulties and disaster in the outcome, the most prudent supervision must be exercised.

The soldiers are to be punished as in the case of an irremissible crime if they offer any affront or violence to the women because, besides being offenses against God, such excesses committed by them could also bring disaster to the entire expedition.

Gálvez had ordered captain Rivera to requisition horses and mules from local Baja California missions without endangering their survival, giving the missionaries receipts for the exact number of animals taken.

[19] On March 24, 1769, Rivera, Crespí, 25 leather-jacketed soldiers, 42 Baja Christian Indians, and 3 muleteers began their journey, driving a large herd of cattle, horses and mules.

Portolá then continued north to explore the Alta California coast and re-establish the port of Monterey visited in 1602 by Sebastián Vizcaíno.

[20] Historians James Rawls and Walton Bean call Gálvez the most effective visitador (inspector general) in the history of New Spain.

"…Although he was a brilliant, forceful, and generally successful administrator," write Rawls and Bean, "he was also unusually vain, selfish, ruthless, deceitful and unstable.

[26] In 1780, he sent a royal dispatch to Teodoro de Croix, Commandant General of the Internal Provinces of New Spain, asking all subjects to donate money to help the American Revolution.

Negotiated by Phillipe Rose Roume de Saint-Laurant, the edict consists of 28 articles governing various forms of land grants to encourage population growth, the naturalization of inhabitants, taxation, the arming of slave owners, the duty and function of a militia to protect the island, and trade and mercantile issues.

Gálvez was a heavy-handed administrator, implementing major reforms in Spanish America to strengthen royal power, promote efficiency, diminish the role of American-born elites, and increase revenues.

One assessment of Gálvez is that "his legacy of a more rational administration was purchased with the political alienation of many Americans and not a few Spaniards, whom he pushed from their traditional places and powers.