Aarsleff was born on 14 August 1852 in Nyborg on the island of Funen. He trained as a wood carver with his father before going to Copenhagen where he studied at the Royal Danish Academy of Fine Arts from 1872 to 1876, at the same time working in the studios of Theobald Stein, Vilhelm Bissen and Jens Adolf Jerichau. In 1876, he won the Academy’s Small Gold Medal and in 1880, its Large Gold Medal. In 1881, he went abroad on a travel grant to further his studies, visiting Paris, Italy and Greece.
Aarsleff’s production of own works was relatively slow to get off the ground. He is best known for a number of statues and statuettes of young adults in a style influenced by Bertel Thorvaldsen and particularly Jerichau. He also made decorative works for several large architectural projects, including the Ny Carlsberg Glyptotek. From 1900 to 1912 he was engaged with the restoration of Margaret I’s sarcophagus at Roskilde Cathedral.