A precocious child, he learned reading, Japanese calligraphy and the Four Books and Five Classics under the tutelage of a priest at a local Buddhist temple.

This increased his interest in history, and he began to deal with the "true relationship between sovereign and subject" (大義 名分 Taigi meibun) from the teaching of Confucius.

He also travelled extensively to meet with other scholars, including Hayashi Shihei in Sendai Domain in 1790, developing a reputation of eccentricity and for a total lack of consideration for his personal appearance.

Although Hayashi Shihei knew of Gamō by reputation, when they first met, he mistook him for a beggar due to his disheveled appearance.

In 1801, he set up a private school called Shusei-an near Kisshō-ji in Komagome, Edo, where he worked on his book entitled "Notes on the Imperial Tombs" (山陵 志 Sanryō-shi).