Mary Hottinger, née Mackie, was born in Liverpool, England, to a Scottish family. Her father John Lindsay Mackie was a customs officer. She studied French and German at Cambridge University and received her MA degree in 1922. During World War I, she worked as translator in the War Office and as a secretary in the Air Ministry. From 1924 to 1926, she taught French at Bedford College of the University of London.
In 1926, she married Markus Hottinger, a Swiss lawyer, with whom she had a daughter and lived in Zurich. She joined the faculty of the University of Zurich as a lecturer in English. Her first translated work, a French biography of Claudio Monteverdi, was published in 1926. Subsequently, she did mostly translations of German works into English, mostly by Swiss authors such as Hugo von Hofmannsthal and Jacob Burckhardt. For her friend Thomas Mann, she translated his lectures into English and practiced with him before his first lecture tour through the USA. After World War II, she became known primarily as the editor of German-language anthologies of crime stories and ghost stories.