Leo Zimmermann was a farmer from the village of Todtmoos in Waldshut, Baden-Württemberg, Germany. Born into a Roman Catholic family on 20 February 1883, he was the son of Joseph Zimmerman and Ludwina Wasmer.

Zimmerman's two brothers Arnold (b. 1881) and Edwin (b. 1886), both labourers, had left Germany and departed from Antwerp, Belgium, arriving in Québec on 17 September 1911. Their intended destination was to Saskatoon, Saskatchewan and early the following year the unmarried Leo was intending to make the same journey to join his siblings.

He purchased ticket number 315082 which cost £7, 17s, 6d from the Swiss agent Kaiser & Cie. in Basel for 390 Swiss francs.  

He boarded the Titanic at Southampton as a third class passenger and stated his destination as to the home of his brother Edwin in Saskatoon. 

He shared cabin (E)58 on F-Deck with Josef Arnold, Anton Kink, Vincenz Kink, Albert Wirz and (probably) Wenzel Linhart. 

Leo Zimmerman died in the sinking and his body, if recovered, was never identified.

His brother Arnold was still living and working as a farmer in Saskatoon at the time of a 1916 census but what became of his thereafter remains unknown.