As a jurist, he anchored the state in liberal democracy, guarded the fragile germ of the rule of law, and embarked on internal reforms.

In implementing the form of government of 1919, Ståhlberg piloted an independent Finland towards acting in world politics; in presidential-led foreign and security policy, he relied on international law and diplomacy.

[2] It was only after the opening of private archives of President J. K. Paasikivi that it was realized that Ståhlberg had a very significant political role as an “éminence grise” until his death.

Ståhlberg soon began a very long career as the presenter and planner of the Senate's legislation, during the period when Finland was a Grand Duchy under Czarist rule.

Ståhlberg served as secretary of the Diet of Finland's finance committee in 1891 before being appointed as an assistant professor of Administrative Law and Economics at the University of Helsinki in 1894.

This appointment to a senior position in the Finnish administration was approved by the new Governor General of Finland, Nikolai Bobrikov, whose term in office saw the beginning of the period of Russification, and whose policies represented all that the constitutionalist Ståhlberg was opposed to.

In 1902, he was dismissed as Protocol Secretary, due to his strict legalist views, and his opposition to legislation on compulsory military service.

The following year he resumed his academic career and was appointed as Professor of Administrative Law at the University of Helsinki, a position he retained until 1918.

During his time in that post he wrote his most influential piece of work, "Finnish administrative law, volumes I & II."

After the February Revolution in 1917, Ståhlberg was backed by the majority of the non-socialists members of Parliament as a candidate to become Vice-Chairman of the Economic Department of the Senate.

Ståhlberg emerged as a candidate for president, with the support of the newly formed National Progressive Party, of which he was a member, and the Agrarian League.

[5] Ståhlberg was inaugurated as the first President of the Republic on the following day, and reluctantly moved out of his home in Helsinki to take up residence in the Presidential Palace.

He pardoned most of the Red prisoners, despite the strong criticism that this aroused from many right-wing Finns, especially the White veterans of the Civil War and several senior army officers.

He signed into law bills that gave the trade unions an equal power with the employers' organizations to negotiate labour contracts, a bill to improve the public care for the poor, and the Lex Kallio law which distributed land from the wealthy landowners to the former tenant farmers and other landless rural people.

He was also cautious towards Germany, and generally unsuccessful in his attempts to establish closer contacts with Poland, the United Kingdom and France.

According to the longtime late Agrarian and Centrist politician Johannes Virolainen, he believed that the incumbent president was too much favoured over the other candidates while standing for re-election.

[12]He was offered the post of Chancellor of the University of Helsinki, but declined it, instead becoming a member of the government's Law Drafting Committee.

Ståhlberg was a National Progressive Party candidate in the 1931 Presidential election, eventually losing to Pehr Evind Svinhufvud by only two votes in the third ballot.

He is generally regarded as a moral and principled defender of democracy and of the rule of law, and as the father of the Finnish Constitution.