His father was Ferenc Káthay, lieutenant of judge royal Gábor Perényi and later served in the Castle of Eger.
Mihály Káthay married twice: his first wife was Anna Drugeth de Homonna, and the second was Margit Mágóchy.
He seriously wounded, along with judge royal Stephen Báthory de Ecsed in the Battle of Hatvan.
learning the refusal, "the soldiers very outraged", "so much that all they wanted to rebel, I found it hard to quiet them" – wrote Káthay to the Chamber in one of his letters dated 1 November 1599.
He had considerable wealth by his second marriage and had a close relationship with the most powerful landowners of Northern Hungary from that time.