He served as a private counselor to Gabino Gaínza during his administration of the State of Guatemala, and it is probably due to his influence that the latter did not strenuously oppose the popular movement for liberty.

[3] Liberal historians such as Ramón Rosa[4] and Lorenzo Montúfar y Rivera,[5] refer that he promoted major innovations in all aspects of the administration, to make it less dependent on the Catholic Church influence.

It is also reported that he made public instruction independent of the Church, fostered science and the arts, eliminated religious festivals as holidays, founded the National Library and the National Museum, promoted respect for the laws and the rights of citizens, guaranteed freedom of the press and freedom of thought, established civil marriage and divorce, respected freedom of association and promulgating the Livingston Code (penal code of Louisiana),[4][5] against much opposition from the population who was not used to the fast pace the changes were taking place; he also initiated judicial reform, reorganized municipal government and established a general head tax which severely impacted the native population.

[6] However, this were all changes that the liberals wanted to implement to eliminate the political and economic power of the aristocrats and of the Catholic Church -whose regular orders were expelled in 1829 and the secular clergy was weakened by means of abolishing mandatory tithing.

The secular clergy that was still in the country, persuaded the uneducated people of the interior that the disease was caused by the poisoning of the springs by order of the government and turned the complaints against Gálvez into a religious war.

José Francisco Barrundia and Pedro Molina, who had been his friends, came to oppose him in the later years of his government after he violently tried to repress the peasant revolt using a scorched earth approach against rural communities.