[1] In his early career, he published on Danish and Arctic nematodes[2][3] and on the zonation of marine algae in Øresund.

[4] Between 1845 and 1848, he travelled extensively in Central America and the Caribbean and published numerous papers on the flora, concentrating on the plant families Acanthaceae and Fagaceae.

[10] He was appointed professor of botany at the University of Copenhagen in 1851, a post he held until 1862.

His studies of what has since been known as juniper-pear rust showed that this fungus annually switches between two hosts; Juniperus sabina is the primary (telial) host and pear, Pyrus communis, is the secondary (aecial) host.

[12] The orchid genus Oerstedella Reichenbach f. is named for him.