Composer. He was recognized as a prolific 19th-century Danish composer of the Romantic Period who was a member of the Hartmann dynasty of at least four generations of composers. He is credited with seven symphonies, concertos for respectively violin, cello, and piano, several overtures, a symphonic poem called "Hakon Jarl," orchestral suites, serenades, ballets, operas, and singspiels, incidental music and cantatas. He composed a host of piano and violin pieces. With his music having Scandinavian folk overtones, his works were mainly published by German editors. His debut production was performed on Easter Sunday of 1858 in the Copenhagen Cathedral. He co-composed August Bournonville's ballet "Fieldstuen," which was first performed at the Royal Theater in Copenhagen in May of 1859 with a long successful run. The same year, he received a scholarship to study music in Germany, along with periods in Paris and Vienna. Upon his return to Denmark in 1861, he held a position as organist at St. Johannes Church in Copenhagen and, later in 1871, at the Christiansborg Palace Chapel as well as tours. Born the oldest child of noted composer J. P. E. Hartmann, he had a problem at the beginning of his career with his compositions being confused with his father's pieces. His mother, Emma, was also a recognized composer and a member of the wealthy Copenhagen family of Zinn. His sister Emma married composer Niels Wilhelm Gade, . Following behind his father and Gade's prosperous reputations, his career was often overshadowed. His sister Clara married composer August Winding with who he co-authored pieces. His brother, Carl Christian Hartmann, became a successful sculptor as well as composed a few pieces. He was educated in music at home by his father. Children's book author Hans Christian Andersen, who was a colleague of his father, mentioned in his letters that he could play music as a toddler before he could speak. He married Bolette Puggaard, a daughter of a wealthy merchant and philanthropist, and purchased a house in the countryside. The couple had three sons and two daughters, who were talented in the arts and music. As his health declined physically, his mental health was a concern, with bouts of depression with personality changes requiring inpatient treatment. Although his music has rallied in the 21st century and is available for purchase, his music fell into oblivion for decades after his death.