In March 1892, Thälmann's parents were convicted and sentenced to two years in prison because they had fenced stolen goods or had taken them for debt payment.

He first lived in an emergency shelter, later in a basement apartment, and in 1904 he was a fireman on the steam-powered freight ship AMERIKA, which also traveled to the United States.

On 1 February 1904, he joined the Central Union of Trade, Transport and Traffic Workers of Germany and ascended to the chairman of the Department Carters.

In 1913, he supported a call of Rosa Luxemburg for a mass strike as a means of action of the SPD to enforce political demands.

[8] In June 1922, terrorists from the ultranationalist group Organisation Consul threw a hand grenade into his ground floor flat; the assassination attempt failed and he survived.

Thälmann's candidacy in the second round of the presidential election split the centre-left vote, ensuring that the conservative Paul von Hindenburg defeated the Centre Party's Wilhelm Marx.

[11] After the Revolution of 1918 and during the Spartacist uprising, the government ordered the suppression of the revolt and the extrajudicial murders of KPD leaders Rosa Luxemburg and Karl Liebknecht by members of the Freikorps.

[11] This followed the events of "Bloody May", in which 32 people were killed by the police in an attempt to suppress demonstrations, which had been banned by the Interior Minister and SPD member Carl Severing.

[14][15] By 1927, Karl Kilbom, the Comintern representative to Germany, had started to combat this ultra-leftist tendency within the KPD but found Stalin machinating against his efforts.

[16] After the Nazis came to power in January 1933, Thälmann proposed that the SPD and KPD should organise a general strike to topple Hitler's rule.

In February 1933, a Central Committee meeting of the then already banned KPD took place at the "Sporthaus Ziegenhals" in Königs Wusterhausen, near Berlin, where Thälmann had called for the violent overthrow of Hitler's government.

The Comintern's guidelines on social democracy as "social fascism" remained in force until 1935, when the Comintern officially switched to endorsing a "popular front" of socialists, liberals, and even conservatives against the fascist threat—an attempt to win over the leftist elements of the NSDAP, especially the SA, who largely came from a working-class background and supported socialist economic policies.

[9] After the Reichstag Fire on 27 February 1933, the Nazi regime targeted members of the KPD and other left-wing opponents of it in a new wave of violence and arrests.

Eight officers of Police Station 121 arrested Thälmann at his self-appointed safehouse, the home of Hans and Martha Kluczynski in Berlin-Charlottenburg.

"[16] Fellow German communist Wilhelm Pieck had managed to escape to the Soviet Union and in July 1936 issued a statement calling for the release of Thälmann.

He stated: "If we succeeded in raising a tremendous storm of protest throughout the world, it will be possible to break down the prison walls and as in the case of Dimitrov, deliver Thälmann from the clutches of the Fascist hangmen.

"[21] A fellow Buchenwald prisoner, Marian Zgoda, recalls hearing the shooting of Thälmann on the 18th—four days after Himmler's curt annotation in his notes.

[5] Shortly after, the Nazis claimed in an announcement that, together with Rudolf Breitscheid, Thälmann had died in an Allied bombing raid on 23 August.

[24] During the Spanish Civil War, several units of German Republican volunteers (most notably the Thälmann Battalion of the International Brigades) were named in his honour.

After 1945, Thälmann and other leading communists who had been murdered, such as Rosa Luxemburg and Karl Liebknecht, were widely honoured in East Germany, with many schools, streets, factories, and the like named after them.

Thälmann, like Luxemburg and Liebknecht, was honoured with a symbolic grave at the Memorial to the Socialists (German: Gedenkstätte der Sozialisten) in the Friedrichsfelde Central Cemetery, Berlin.

[28] One of the main traffic arteries of Soviet Riga was named Ernsta Tēlmaņa iela after him on completion in 1981; however, soon after Latvia had regained independence in 1991 it was renamed Kārļa Ulmaņa gatve, after pre-World War II prime minister Kārlis Ulmanis.