Yoshikatsu served as a member of the cavalry for Nobunaga, and may have started as a koshō, or assistant to senior bushō.
In 1560, he assisted Hattori Kazutada after Kazutada had sustained an injury, and killed Imagawa Yoshimoto during the attack. One of his fingers was severed in the attack.
Yoshikatsu is known as one of the elite warriors selected to have a black horo, a type of silk cape that would inflate on the back of cavalry and serve to deflect arrows and rocks thrown from behind.
After Nobunaga marched upon Kyōtō, in 1569, Yoshikatsu joined in the Battle of Okawachi Castle primarily as a messenger. As a close advisor to Nobunaga, he served with the 尺限廻番衆（さくきわまわりばんしゅう）に属し、判物や書状に署名を残した。
In 1582, Yoshikatsu accompanied Nobunaga in
During the Honnō Temple Incident, he lodged in Kyōtō, and after the coup, took refuge in the Nijō residence with Nobunaga’s eldest son, Nobutada, but died with during the ensuing combat.