William Henry Kirkman was the Kirkman's first-born child. Born in Idaho in 1868, he moved with his parents to Walla Walla in the early 1870s. He attended local schools, Whitman College, and Boston University, where he studied law. William Henry returned to Walla Walla and practiced as an attorney for a few years. He then joined the Kirkman Company and was involved in the running of its various businesses, farms and ranches. He served for a time as Clerk of the U. S. District Court and was a member of the city council, school board and Elks Club. He married Maude Ashley and they had one son, William Leslie, but Maude died young. After his wife's death, William Henry and his little boy came to live with Isabella at Kirkman House which the family referred to as the “Red Brick House.”
In 1928 he was the driver on a family trip north when, near Colfax, Washington, the car overturned and crushed him. His nephew who was following in a another car speculated that he had a heart attack. His passengers, all family members, sustained slight injuries but William Henry died at the scene. He was 60 years old.
At his death he was anticipating retirement from a position as state senator from the Eleventh district which he held during the 1925 and 1927 sessions. He was a candidate on the Republican ticket in the primaries for lieutenant governor and polled a heavy vote in his home county. He was prominent in public life in the city, county and state for many years.