Later, he left Denmark in 1862 to study music in Berlin, with Hans von Bülow, and Paris where he was a protégé of Hector Berlioz.
In 1871 he was offered the post of director of the Peabody Institute in Baltimore, Maryland, where his influence won praise from influential visitors including Tchaikovsky and Arthur Sullivan.
Hamerik was an influential teacher in the US, as the director of Peabody in Baltimore for over a quarter of a century; and his works were performed in both the United States and Europe.
His later work incorporates influences from composers such as Paul Dukas and César Franck and the more roving harmony and extended tonality, including movements in different keys and expanded use of vagrant chords.
with Mahler's works from the same period, involving hundreds of musicians in its first performance in Baltimore, which was directed by fellow von Bülow student Joseph Pache.