Hobbies:
Kido enjoyed collecting swords, acquiring paintings, writing poetry, and browsing antique shops. He apparently was a proponent of traditional culture, was an enthusiast of the tea ceremony and calligraphy. He played go, enjoyed sumo and wrote comic haiku.

His Household:
According to the intro to the diaries, Kido had 20-25 persons in his household, consisting of his wife Matsu, his adopted son, various protégés, and Choshu students in Tokyo.

From an account by A.B. Mitford, Matsu had none of the shyness characteristic of Japanese women. Kido-san and his wife were a happy couple. (Mitford stated she was "a bonny little lady, though eyes less familiar with the custom than mine would have objected to the disfigurement of shaven eyebrows and blackened teeth." A former geisha, she had "none of the shyness which I usually met with in Japanese ladies"; and she brought out her samisen to accompany her song after dinner.)

His adopted son Katsusaburo (nephew by elder half-sister) died in 1867. Shojiro was the successor (nephew by younger sister Haruko), and was 10 in 1868. This successor learned English and departed in 1871 for Brighton, England.

Odd notes:
He affected Western clothing and hair in 1871. Apparently, he eventually switched his allegiance over to foreign doctors. (Note that his father had studied some Dutch medicine, which probably made him more receptive to western medicine.)

However, Kido never wanted to fully disregard traditional Japanese ways and in one instance was reported to have lamented over the behavior of a particular diplomatic emissary who he felt had completely cast off Japanese-ness in their interactions with foreigners.

He was apparently quite friendly to foreigners.