Both of Karl Hård af Segerstad's parents were Swedish nationals, and throughout his life he retained strong ties to Sweden, although he was born and lived in Finland.
His high demands on himself led to a quickly deteriorating health and he died in Helsinki in 1931 at the age of 58.
During his time in Vyborg, he designed both tenement houses and a large covered market building.
After his return to Helsinki he continued designing schools, a library, and another covered market.
At city architect of Helsinki, he was in part responsible for social housing and planning issues.