He joined the Communist Party of Germany (KPD) in 1920 and took several courses at the Marxist Workers' School.

By the end of 1932, The KPD was the third largest party in Germany, with 3,600,000 members and had received some six million votes in the previous election.

The Reichstag Fire Decree pushed by Adolf Hitler in response to the Reichstag fire on February 27, 1933, and signed into law by President Paul von Hindenburg withdrew civil liberties and enabled the Nazis, then in key positions in government, to arrest anyone they deemed to be an enemy.

In the first weeks of March 1933, there were 11,000 Communists arrested and by June 1933, more than half of the KPD district leaders were in detention.

Through his relationships with Wilhelm Guddorf, John Sieg and others, he was in regular contact with the Red Orchestra and with groups in Hamburg, Mannheim, Leipzig, Munich and elsewhere.

[3] Uhrig and Römer published an underground paper, called Informationdienst ("Information Service"), one of the most important Resistance newspapers.