He married Princess Margarita of Hohenlohe-Öhringen on 8 June 1984.
He had one daughter by this marriage, Princess Cécilia of Leiningen (born 10 June 1988).
Princess Margarita died in 1989 in a car accident.

On 24 May 1991, Prince Karl Emich married Gabriele Renate Thyssen.
After an inheritance dispute, he desisted claim to the family's legacy in favour of his younger brother Andreas, 8th Prince of Leiningen.
The couple had one daughter, Princess Theresa Anna Elisabeth of Leiningen (born 16 April 1992) In 1998, Karl Emich and Gabriele were divorced.

He married Countess Isabelle von und zu Egloffstein in a civil ceremony on 8 September 2007 in Amorbach, and in a religious ceremony on 7 June 2008 in Pappenheim (she descends from the mediatised counts of Pappenheim).
On 12 April 2010, they had a son, Prince Emich of Leiningen.

When they wed, Gabriele Thyssen was a Roman Catholic and Karl Emich a British dynast, as a legitimate descendant of George II of Great Britain (through his granddaughter Augusta of Wales (1776-1813), ancestress of Karl Emich's mother, Eilika of Oldenburg) at which time a provision of the Act of Settlement 1701 stipulated that in the event the British crown is to devolve upon an heir married to Roman Catholic, that heir is permanently disabled from succeeding to the throne, which would pass instead to the next Protestant in the order of succession who had not been married to a Roman Catholic.
The Succession to the Throne Act, 2013, repealed that marital restriction (also embodied in the Bill of Rights 1689), with retroactive effect, as of 26 March 2015.
He married Princess Margarita of Hohenlohe-Öhringen on 8 June 1984. He had one daughter by this marriage, Princess Cécilia of Leiningen (born 10 June 1988). Princess Margarita died in 1989 in a car accident.
On 24 May 1991, Prince Karl Emich married Gabriele Renate Thyssen. After an inheritance dispute, he desisted claim to the family's legacy in favour of his younger brother Andreas, 8th Prince of Leiningen. The couple had one daughter, Princess Theresa Anna Elisabeth of Leiningen (born 16 April 1992) In 1998, Karl Emich and Gabriele were divorced.
He married Countess Isabelle von und zu Egloffstein in a civil ceremony on 8 September 2007 in Amorbach, and in a religious ceremony on 7 June 2008 in Pappenheim (she descends from the mediatised counts of Pappenheim). On 12 April 2010, they had a son, Prince Emich of Leiningen.
When they wed, Gabriele Thyssen was a Roman Catholic and Karl Emich a British dynast, as a legitimate descendant of George II of Great Britain (through his granddaughter Augusta of Wales (1776-1813), ancestress of Karl Emich's mother, Eilika of Oldenburg) at which time a provision of the Act of Settlement 1701 stipulated that in the event the British crown is to devolve upon an heir married to Roman Catholic, that heir is permanently disabled from succeeding to the throne, which would pass instead to the next Protestant in the order of succession who had not been married to a Roman Catholic. The Succession to the Throne Act, 2013, repealed that marital restriction (also embodied in the Bill of Rights 1689), with retroactive effect, as of 26 March 2015.
Prince Karl Emich of Leiningen