He created a new set of guidelines for good book design and invented the popular Futura, a geometric sans-serif font used by many typographers throughout the 20th century and today.

Renner was a friend of the German typographer Jan Tschichold and a key participant in the heated ideological and artistic debates of that time.

Even before 1932, Renner made his opposition to the Nazis very clear, notably in his book “Kulturbolschewismus?” (Cultural Bolshevism?).

While designing his typeface Futura, Renner appeared at a public forum in Munich with several other German authors to speak out against the Nazis and other right-leaning parties who criticized anything that deviated from tradition as being "cultural bolshevism.

"[1] After the Nazis seized power in March 1933, Renner was arrested and dismissed from his post in Munich in 1933, and subsequently emigrated to Switzerland.