Born the son of an engineer in Brackenheim, Baden-Württemberg, Heuss went to school in nearby Heilbronn before studying art history and political science in Munich and Berlin.
Before graduating, Heuss was already active in the left-wing liberal party Freisinnige Vereinigung (Free-Minded Union) and a close friend of party MP Friedrich Naumann.
From 1905 he edited the party newspaper Die Hilfe (The Help) in Berlin before editing the Heilbronn-based Neckarzeitung from 1912-18.
In 1908 he also married Elly Heuss-Knapp, who was to become his lifelong companion and political ally.
In 1918, he returned to Berlin, where he was a teacher at the Political University as well as editing the weekly paper Deutsche Politik and becoming a founding member of the German Democratic Party (DDP).
Heuss was almost immediately elected to the Berlin legislative assembly, and later entered the Reichstag (parliament) of the Weimar Republic as MP for Berlin's Schöneberg district, serving from 1924-28 and 1930-33.
A formative experience during these early years of political engagement was a trip to Greece in 1931, ostensibly to take part in a conference of European liberal parties.
In fact, Heuss took the opportunity to travel around Greece, publishing a string of articles about the Greek landscape, the plight of refugees from Turkey and industrialisation.
Hitler's rise to power
On March 23rd 1933, a black mark appeared on Heuss' career when he voted in favour of the Ermächtigungsgesetz – the law granting Hitler emergency powers - which cemented the dictatorship for the coming years.
Heuss voted only reluctantly in favour of the law so as not to break ranks with the rest of his party. Of the five DDP MPs, three were for supporting Hitler and two against.
He had already tried to convince them to vote against it and had written a draft speech to give in the chamber explaining his vote.
Heuss had long been an opponent of Hitler, publishing a book called Hitler's Way explaining the dangers of Nazism in 1932.
That book cost him his mandate as an MP and his job at the Political University after the Nazis swept to power, with the final indignity of seeing three of his books – including Hitler's Way — burned with books considered subversive to the Nazi regime.
But Heuss was far from a total opponent of the Hitler regime in the early years.
He argued in Die Hilfe that the burning of books and the boycott of Jewish businesses could be seen as the German people “protecting themselves” against the “press of the world” and rubbished reports of pogroms in Germany.
His opinions are hard to untangle during this period, with some of his letters containing disparaging references to the “Jewish literati” targeted by the Nazis while at the same time he helped some of his Jewish friends and their families emigrate.
Shut out of politics
Heuss was banned from publishing Die Hilfe in 1936 after years of fierce political pressure from the Nazis, and he and Elly survived the following years of dictatorship with a variety of writing and advertising jobs.
Until the Nazis banned newspapers from publishing his articles in 1941, he wrote for their weekly paper Das Reich.
Later, he used the pseudonym Thomas Brackheim to continue writing in various newspapers, as well as publishing biographies of historical figures including his mentor Friedrich Naumann, who founded Die Hilfe.
After moving to Heidelberg in 1943, Heuss received permission from the American occupation authority to begin publishing the Rhein-Neckar Zeitung – which still exists today — in 1945, and began teaching history at the Technical University.
After the war
In his later writing, Heuss would call May 8th 1945 – the day of Germany's capitulation – “one of the worst days in German history”, but also one that would finally allow an “un-cramping” of the German people.
Heuss' personal response to the Holocuast was nuanced. He rejected the idea that the German people bore a “collective guilt” as an “oversimplification” - but accepted that the nation must feel “collective shame” at what was done in their name.
He joined the Democratic People's Party (DVP), becoming president before it joined the other West German liberal parties in the founding of the Free Democratic Party (FDP), becoming its first president in 1948.
Elly was elected to the Baden-Württemberg state assembly for both the DVP and later the FDP, continuing the political career she had begun with the DDP under the Weimar Republic.
Heuss took part in the Parliamentary Assembly which agreed on the form of the Constitution of the Federal Republic of Germany in 1948 before being elected to the first-ever Bundestag as leader of the FDP group.
But he almost immediately gave up his mandate when he was elected President of the Republic over Social Democratic Party (SPD) candidate Kurt Schumacher.
Elly also decided reluctantly to give up her seat in the state parliament and support her husband, but died less than three years into Heuss' term of office.
President of the Republic
Heuss' first aim as President – a largely ceremonial role – was to bring the cultural life of Germany back into being after its smashing by the Nazi dictatorship.
He aimed to reclaim industry from its militant usage under the Nazis, and was one of the first politicians to support the industrial design movement that would make German products so desirable worldwide.
And he created the Order of Service to the Federal Republic of Germany, known as the Federal Service Cross (Bundesverdienstkreuz) to honour public-spirited citizens, as well as reviving the order Pour le Merite (for service) created by Frederick the Great.
One of his best-known actions was push for the alteration of the national anthem in 1952, coming into conflict with then-Chancellor Konrad Adenauer, who was against any change.
But eventually, Heuss' pressure helped Adenauer and opposition leader Schumacher agree on updating the national song – although it wasn't Heuss' preferred option.
They kept Haydn's original tune (the famous “Deutschland, Deutschland über alles...”) but replaced the words with the third verse of the lyrics written by poet August Heinrich Hoffmann in 1841:
Unity and justice and freedom
for the German fatherland!
Let us all strive for them together
brotherly with heart and hand!
Unity and justice and freedom
are the pledge of happiness-
bloom in the glow of happiness
bloom, German fatherland!
Bringing Germany back to the world
Later in his time in office, Heuss began the first state visits after the war in a bid to show the world the new, democratic face of Germany – but he faced high hurdles, as no country wanted to be the first to invite a German President.
Greece was the first to break ranks after the German brother-in-law of the Greek King Paul lobbied on Heuss's behalf, allowing Heuss to return in state to the country which had made such an impression on him in 1931.
He called it a “return to my own spiritual home”, while the two countries quickly signed cultural and education agreements in the wake of the visit.
That visit was such a success that was swiftly followed by visits to Turkey and Italy – including the Vatican — in 1957, and in 1958 he visited Canada, the US and the UK, giving speeches in his own words – he employed no speechwriter – in each country.
Heuss' time in office came to an end in 1959, and he retired to Stuttgart to write his memoirs. That same year he was honoured with the Freedom Prize of the German Publishing Industry.
After his death in 1963, a foundation was set up to award the Theodor Heuss Prize each year to recognize exemplary democratic actions.