Kammala jumla mai zuwa: An haife shi a Orlando, Florida, Harrison ɗan tagwayen ɗan'uwansa ne na ɗan'uwansa Calvin Harrison. Shekara guda kafin kokarin su na farko na shiga tawagar Olympics, tagwayen suna zaune a cikin Ford Mustang. Yayin da Calvin ya kasance tauraruwa a makarantar sakandare, yana kafa Rikodin Makarantar Sakandare ta Kasa a cikin mita 400, Alvin ne ya sami lambar farko ta Olympics a 1996 a Gasar Wasannin Olympics ta 1996. Yayin da ya yi wasan karshe a tseren mita 400, ya zana layi na daya kuma ya gama na hudu a bayan wasan zinare na Michael Johnson. Amma Johnson ya ji rauni ya kafa tarihin duniya a tseren mita 200. Ba tare da lambar zinare ba kuma ba tare da mai riƙe da tarihin duniya Butch Reynolds ba, ƙungiyar Amurka ta kasance mai rauni a cikin
4 x 400 mita relay. Tawagar Burtaniya ta nemi cin gajiyar ta hanyar fita da ƙarfi a cikin jagora, duk da haka a matsayin mataki na biyu na ƙungiyar, Alvin ya ɗauki Jamie Baulch a kan shimfiɗar gida don sanya Amurka a cikin jagora, jagorar da ba za su daina ba, suna ba Alvin lambar zinare.