He briefly returned to Vaduz for a year of internship in his father's medical practice in before he received a doctorate in medicine at the University of Erlangen–Nuremberg in Bavaria.

[3] From 1830 to 1837, Schädler ran a medical practice in Bad Ems in the Duchy of Nassau, and from 1833 to 1838, he was a military doctor for a Graubünden battalion.

[3] The aim of the revolution was to improve the economic and political situation of ordinary citizens in Liechtenstein, primarily fuelled by the worsening economy in the country in the years prior.

The primary task of the council was the creation the draft for a new Liechtenstein constitution, of which the work was done primarily by himself and Michael Menzinger.

[3] Peter Kaiser withdrew from politics in November, and Schädler was elected as his successor as the Liechtenstein representative at the National Assembly in Frankfurt the following month.

Regarding Pan-Germanism, he supported the movement under Austrian leadership, as he believed that the formation of a German state without Austria would have isolated Liechtenstein and put the country's sovereignty at risk.

Notably, Schädler was pessimistic about the future of Liechtenstein, believing that with the rise of Pan-Germanism the country was more suited to be annexed into Austria.

A major challenge faced by Schädler was the legal reduction in local community autonomy on a national level and he created new municipal regulations.

In 1850, he formally raised the question with Aloys II and appealed for him to propose a union to Franz Joseph I of Austria.

[12] After the failure of the revolution in Germany, Aloys II suspended the constitutional council and disbanded the office of District Administrator on 20 July 1852.

[3] The draft was reviewed by an unknown German legal expert and formed the basis of the 1862 Constitution of Liechtenstein, which was ratified on 26 September.

Upon the opening of the Landtag of Liechtenstein on 29 December 1862, he gave a speech and declared that its intention was to allow for the economic and cultural development of the country as well as making ordinary citizens aware of their liberties and political rights.

For example, during the Second Schleswig War in 1864, Johann II supported the cause of both Austria and Prussia, whereas the Landtag had protest voted against the use of military force against Denmark.

[19] It was this, in combination to the rising costs of maintaining it, that led to the Liechtenstein military being disbanded in 1868 and the country declaring its permanent neutrality.