Succeeding to the throne in 1895, Alexander had his power exercised by a regent throughout his reign on account of his mental illness.

Lippe's diet confirmed Prince Adolf as regent on 24 April 1895, pending a settlement over the disputed regency.

[3] A settlement was reached in 1897 when a commission under the presidency of King Albert of Saxony ruled in favour of the claims of Count Ernst of Lippe-Biesterfeld.

[4] Prince Adolf then resigned the regency and was replaced by Count Ernst, who would rule until his death in 1904 as regent for Alexander.

While unable to exercise power Alexander lived at the sanatorium of St Gilgenberg near Bayreuth, where he would often be seen attending concerts and the theatre.