Tuhia he tomokanga mo tenei waahanga - I heke a Guthe ki te United States i te raumati o te tau 1892 ki te marena ki a Clara Belle Ware (1867-1947), no Grand Rapids, Michigan. I tutaki te tokorua i te haerenga a Ware ki Tiamana i te 1890-91. I te tau 1893 i whiwhi ia i te tūranga hei kaiako i roto i te ahupūngao i te Whare Wānanga o Michigan, a i te tau 1900 i whakatairangahia ia hei Kaihauturu Ahorangi. I te tau 1903, ka riro a Guthe hei Kaiawhina Pihika i te tari National Bureau of Standards i Washington, DC (i tenei wa ko te National Institute of Standards and Technology). I te tau 1905 i whakaae ia ki te tono kia noho hei Ahorangi o te Pihikete me te Tiamana o te Tari Pihikete i te Whare Waananga o Iowa. Ko Guthe he mema o te huinga o nga tohu i te St. Louis Exposition
i te tau 1904, ā, ko ia te tumuaki tuarua o te American Association for the Advancement of Science i te tau 1908. I te tau 1909 i tono te Whare Wananga o Michigan ki a Guthe kia hoki mai hei Kaiwhakaako tuuturu i te Tari Pihikete, a ka hoki mai ia ki Ann Arbor me tana whanau taiohi. I te tau 1912 i whakaingoatia a Guthe hei Dean o te Kura Tuarua hou i te Whare Waananga o Michigan.