Kathleen Willisher was born in England in 1905 and immigrated to Canada in 1930. She was a graduate of the London School of Economics and, in February 1946, was an employee of the High Commissioner's Office for the United Kingdom. Willisher was a member of the Labour Progressive Party and was recruited into a study group by Agatha Chapman in 1942. According to the espionage commission's final report, Willisher was consciously aware that the information she divulged in the study group was being passed on to members of the Soviet embassy through Fred Rose. She eventually suffered the same fate as Emma Woikin: Willisher plead guilty and was sentenced to three years in prison

In their final report, the espionage commission writes of Willisher:

"Miss Willsher was an employee of the Office of the High Commissioner for the United Kingdom at Ottawa. She came to Canada in 1930 at the age of twenty-five as a stenographer. In due course she was promoted and in 1944 she became assistant registrar, having been in the registry division of the office since 1939. She is a graduate of the London School of Economics and speaks French, German and some Russian. Her duties as assistant registrar involved the entering or registration of incoming and outgoing letters and telegrams, by reason of which she had access, with a very few exceptions, to all files containing documents of a highly secret nature."