John I, Count of Holstein-Kiel was a member of the House of Schauenburg.
John was the eldest son of Count Adolf IV of Schauenburg and Holstein and his wife Heilwig of Lippe. After his father retired to the monastery in 1239, John ruled jointly with his younger brother Gerhard I, initially under regency.
He was Count of Holstein-Kiel from 1261 until his death. In 1255, they signed a trade agreement with Lübeck. In 1261, the county was divided.
John chose Kiel as his residence.
Gerhard chose Itzehoe. When Denmark ceded Rendsburg, it went to Gerhard.
John died in 1263. However, in 1273, they divided their territory into Holstein-Segeberg and Holstein-Kiel.
When Adolf died without an hier in 1308, the two parts were reunited. The inscription in his seal read: South (IGILLUM) * IOH (ANN) * Instruction Section * STORM Comitis WAGRIE * ARIA * ET * HOLTSACIE (of John, Count of Stormarn, Wagria and Holstein).
In the middle: SCOVENBG COMES(Count of Schauenburg).