In 1577, he had to concede the revenue from Harpstedt, Delmenhorst, Varel and some minor castles to his younger brother Anthony II for a 10-year period.

In 1597, the Aulic Council ordered that the County of Delmenhorst be split off from Oldenburg; this separation would last until 1647.

In 1596, John VII attempted to dam the Schwarze Brack, in order to create a land link from Oldenburg to Jever.

John VII nevertheless earned the nickname "dike builder" with his costly land reclamation projects in Butjadingen and the Jade Bight.

He reorganized the administration and the judiciary and modernized the organization of the Lutheran Church in Oldenburg.