Following graduation he remained in Prague as an assistant to pathologist Edwin Klebs.

He was a prolific author, one of his better efforts being Klinische Diagnostik innerer Krankheiten (1882),[4] a work that was published over several editions and later translated into English as Clinical diagnosis : the bacteriological, chemical, and microscopical evidence of disease.

On his initiative he started with the construction of a new, much more modern and hygienic designed clinic that was opened in 1899.

Jaksch was awarded in 1899 for this construction of his permanent bathrooms at the nursing exhibition in Berlin.

[5] In urine Jaksch discovered acetoacetic acid, a melanin probe and manganese toxicosis.