- Princess Alexandra of Sayn-Wittenstein-Berleburg (1970)
- Count Jefferson von Pfeil und Klein-Ellgith (1967, m. 1998)
- Count Friedrich Richard Oscar Jefferson von Pfeil und Klein-Ellguth(1999)
- Countess Ingrid Alexandra Irma Astrid Benedikte von Pfeil und Klein-Ellguth (2003)
- Princess Nathalie of Sayn-Wittenstein-Berleburg (1975)
- Mr. Alexander Johannsmann (1977, m. 2011)
- Master Konstantin Gustav Heinrich Richard Johannsmann (2010)
- Miss Louisa Johannsmann (2015)
He was raised in Germany, alongside his two sisters. However, in their adult lives, he is the only one who still resides there. Princess Alexandra has since moved to France and Princess Nathalie resides in Denmark.At present, he is unmarried and in a long-term relationship with former American model and children's book author-illustrator Carina Axelsson. If he should remain unmarried and childless at his death, the Sayn-Wittengenstein-Berleburg throne will pass to his uncle Prince Robin zu Sayn-Wittgenstein-Berleburg or to his cousin, Prince Sebastian of Sayn-Wittgenstein-Berleburg. He and his sisters are not in succession for the Danish throne due to their grandfather stipulating that they must be raised in Denmark in order to have succession rights.
He shares a birthday with Archduchess Zsófia Mária Tatjana Monika Erzsébet Katalin von Hasburg (Sophie Maria Tatiana Elisabeth Catherine).