The name of the settlement was originally Keveháza (house of Keve), then Keveaszó, (Cuwe azoa, Keueozou), later Keazó, and finally Kajászó with today's pronunciation.

Towards the end of the Turkish occupation, following a series of lootings, Kajászó was completely depopulated by 1686, and only around 1710 did landowners return.

Between the two world wars, Kajászó flourished again: mainly from milk production, as nearby Budapest was a huge market.

During the World War II, the front line crossed over Kajászó several times, and the destruction was correspondingly enormous.

For an extended time, Kajászó was left out of most national development projects and public works.

The proximity of the highway, the varied but gentle topography, and the excellent soil quality for horses are ideal for the sport.

As the closest large area suitable for riding on the "Buda side" of the capital, the landscape regularly attracts equestrian enthusiasts.

The first mayor of the village after the regime change, Gábor Böcz, previously headed Kajászó for three years, between 1987 and 1990 as chairman of the council.

The interesting thing about the municipal elections held on October 20, 2002, in Kajászó was that a total of 7 candidates ran for the title of mayor of the village, well above the national average.

During the 2011 census, 85.3% of the population described themselves as Hungarian, 0.4% as Gypsy, and 0.7% as German (14.6% did not declare; due to dual identities, the total may be greater than 100%) .