Anton Bernhardt Julius Lemmer was born in Altona, Hamburg, Germany, probably in 1870 or 1871, the son of Adolf Lemmer, an agent, and his wife, Alivine Schostach. He was educated at music schools in Berlin and Hamburg and at the age of 18, when he became liable for military conscription, he decided to leave Germany and settle in New South Wales. He married Amy Wilson Sweeting at Sydney in 1896. There were two sons of the marriage: Adolf, born about 1897 in Sydney, and Siegfried, born in 1903 in Nelson, New Zealand.
In August 1899, the composer Alfred Hill, then living in Sydney, recommended that Lemmer be appointed principal of the Nelson School of Music and conductor of the Nelson Harmonic Society. He arrived in Nelson with his wife and son on 4 September. Later that week he conducted the chorus of the Harmonic Society for the first time. Both they and F. G. Gibbs, secretary of the School of Music, were much pleased with him. Gibbs was to become a constant and faithful friend to Lemmer and his family. They shared many evenings of music and conversation, as well as tramping parties in the Nelson mountains.
Lemmer took up his duties at the School of Music in time to make arrangements for that year's examinations. After a year he drew up plans for teaching theoretical subjects – harmony, counterpoint and composition; the last was especially needed by the advanced students. He set very high standards: Gibbs often had to smooth ruffled feathers among the members of the Harmonic Society when the young conductor, frustrated by the failure of the local choir to achieve the standard of excellence he was aiming for, lost his temper. Nevertheless, his first concert in December 1899 was enthusiastically received. Gibbs recorded that it was the society's best performance, and that they had been warmly congratulated on it.
At the time of Lemmer's arrival in Nelson, plans were already under way for building a permanent home for the School of Music; it had spent its first five years in the Harmonic Society's tiny wooden hall where it occupied two small rooms at the back. Enormous effort and enthusiasm among some Nelson citizens resulted in the opening of the new building on 4 September 1901 by Lady Ranfurly, wife of the governor of New Zealand. The opening was celebrated with a concert prepared by Lemmer, who composed the music for the opening ode, and was praised for his 'unstinted efforts and musical genius'.
Julius Lemmer's professional skills in teaching and administration led to a period of great development and progress in the musical life of Nelson. Besides the establishment of a local diploma at the end of a three-year course, the School of Music now prepared its students for overseas examinations; a number achieved recognition in Europe. The concerts given by the Harmonic Society under Lemmer's baton became a vital part of cultural life in the city.
Lemmer was granted study leave in 1913. During a stay in London, he studied at the London Academy of Music and paid a short visit to his birthplace in Hamburg. The outbreak of the First World War prompted his return to Nelson at the beginning of 1915. He offered to resign if the trustees of the School of Music considered his German birth would in any way disadvantage the school; they assured him of their complete satisfaction with his loyalty, and recorded their belief that the work of the school would benefit greatly from Lemmer's experience in London. Lemmer busily arranged new classes in voice and aural culture.
Unfortunately, not all Nelsonians were as tolerant. Lemmer was a naturalised British subject, and had consented to his son Adolf, although under the minimum legal age, volunteering for active service overseas. In spite of this, an ugly campaign of opposition to Lemmer on account of his German origin was mounted by some influential citizens. His British nationality saved him from being deprived of his teaching position, as G. W. von Zedlitz was at Victoria University College. His son's death in France in 1918 served only to aggravate the opposition. The trustees, particularly Gibbs and Joseph Cock (who had also lost a son on active service), took up Lemmer's cause and defended him boldly both in the press and at an acrimonious meeting of electors during the winter of 1918.
In the years after the war Lemmer continued to influence the musical life of Nelson, although the numbers of pupils sharply declined during the depression of the 1930s. Over nearly two generations he taught young Nelsonians the violin at the School of Music and at the various colleges. He is remembered as the composer of the music of the Nelson College school song. He was well known overseas as well as locally, and was frequently visited by musicians and actors on tour.
With the winding up of the Nelson Harmonic Society in 1937 Lemmer felt it was time to hand over his position at the School of Music to a younger man, but was persuaded to stay on. When he again wished to resign in 1940 the war in Europe made it difficult to find a replacement, and he consented to continue in his post until it was possible to make a new appointment. He relinquished part of his salary to help the school cope with financial difficulties.
Julius Lemmer finally retired at the end of 1944 after being at the centre of musical life in Nelson for 45 years. Amy Lemmer died in 1950 and Julius lived quietly on, enjoying his new hobby of playing bowls with old pupils and colleagues. He died at Nelson on 17 September 1957. The Nelson School of Music remembers him with the Lemmer Scholarship.