After attending school for a few years he worked as an apprentice to a baker and developed a strong interest in natural history, also becoming skilled in taxidermy.
[2] Much of Reischek's early work in New Zealand centred on the museums in Christchurch, Auckland (where he was employed between 1880 and 1888)[4] and Whanganui but, after his initial two-year contract was completed, he made several extended collecting expeditions over the next ten years, covering most of New Zealand and its sub-Antarctic islands, collecting biological and ethnographical specimens, including Māori skulls and mummified cadavers robbed from burial sites.
His ornithological collecting has been subsequently criticised for such reckless actions as shooting 150 specimens of the rare stitchbird on Little Barrier Island at a time when it had become extinct everywhere else.
Ornithological specimens alone numbered over 3000, including many of now extinct species such as the huia, and is one of the most complete in existence of New Zealand's birds.
The collection was eventually bought by friends of Reischek and presented to the Imperial Natural History Museum in Vienna.