In 1603, Akimitsu handed over the headship of the family to his legitimate son Yoshimune, but in 1610 when Yoshimitsu died at the age of 34, Akimitsu returned to Kakuda-jo Castle and attended to government affairs.
慶長8年（1603年）、家督を嫡男石川義宗に譲るが、慶長15年（1610年）、義宗が34歳で没すると、昭光は角田城に戻って政務を執る。