Johann Georg was the only surviving son of Count Eitel Friedrich IV of Hohenzollern-Hechingen (1545–1605) from his second marriage with Countess Sibylle von Zimmern (1558–1599), daughter of Count Froben Christoph of Zimmern.
Together with Johann Pistorius, the tried, in vain, to persuade margrave Georg Friedrich of Baden-Durlach to revert to Catholicism.
In 1620, Emperor Ferdinand II made Johann Georg a Knight of the Order of the Golden Fleece and in on 23 March 1623, he was made an Imperial Prince, together with 22 other imperial counts, including the counts of Hohenzollern-Sigmaringen and Hohenzollern-Haigerloch.
With this elevation, Ferdinand attempted to restore the balance between Catholic and Protestant princes.
Johann Georg married on 11 October 1598 in the Friedrichsburg in Hechingen with Countess Franziska von Salm-Neufville (d. 1619), daughter of Wild- and Rhinegrave Friedrich I of Salm-Neufville (1547–1608) and his wife, Countess Franziska von Salm (d. 1587).