Epigraphers originally identified him by the nickname "Smoking Frog", a description of his name glyph, but later deciphered it as Siyaj Kʼakʼ, meaning "Fire is born".
Originally from Teotihuacan or very closely allied with that city, Siyaj Kʼakʼ was a warlord in the Maya heartland of the Petén (modern Guatemala) during the fourth century.
Siyaj Kʼakʼ remained a power in the region until his death early in the fifth century, acting as overlord to such kings as Yax Nuun Ayiin I (aka "Curl Nose") of Tikal.
The appearance of Siyah Kʼakʼ marks the beginning of a strong cultural influx from the Valley of Mexico, although whether this was accomplished via peaceful interaction or military invasion is still being very actively debated.
The history of Siyaj K'ak is referenced in the fiction novel, The Legend of the Jaguar King, by Anand Jay, where the protagonist, Ayush Mahavir, visits the rumoured location of his tomb in the city of Uaxactun, Guatemala.