Kammala wannan jumlar: An haife shi a garin Spencertown, New York a shekara ta 1782 ga iyaye Mollie Robbins Ketchum da Jesse Ketchum Senior. Bayan mahaifiyarsa ta mutu, an kai shi gidan iyaye masu kula da yara; mahaifinsa mai kula da shi mai yin fata ne. Ya gudu daga gida a 1799 kuma ya shiga ɗan'uwansa Seneca (1780-1850), wanda ke noma a arewacin York (York Mills, yanzu wani ɓangare na Toronto) a Upper Canada. A farkon War of 1812, ya sayi wani tannery daga wani sabon baƙo daga Amurka wanda ya yanke shawarar komawa can bayan an bayyana yakin. Ketchum ya shiga cikin 'yan bindiga na gida, amma an yi tambaya game da amincinsa bayan da Amurkawa suka kama York na ɗan lokaci. Bayan yakin, ya taimaka wajen tallafawa sake gina gadoji a kan Kogin Don kuma ya ba da gudummawa ga gina makarantar farko ta farko a York. An san Ketchum da sha'awarsa mai yawa da kuma amfani a makarantu, halayyar da ta sa ya sami taken ƙauna, "Uba Ketchum". Ya koyar da makarantar Lahadi a cocin Methodist, wanda ya taimaka ya kafa a yankin. Ya yi adawa da ikon mallakar malamai ta cocin Anglican kuma an san shi a matsayin mai adawa da Family Compact. A shekara ta 1828, an zabe shi don wakiltar York a Majalisar Dokoki ta 10 na Upper Canada; an sake zabarsa a 1830 amma bai sake gudu ba a 1834. Kodayake ya goyi bayan William Lyon Mackenzie a cikin majalisar, bai shiga cikin
Tawaye na Upper Kanada.