Fuchs was born in Heilbronn on 11 June 1903 He was nurtured in the Swabian culture of Esslingen and Cannstatt and attended minor seminaries in Schoental and Urach (1918–22).
His student years at Tübingen (1922–24, 1925–27) and Marburg (1924–25, 1927–29) during the heyday of dialectical theology were indelibly stamped by the theology of Karl Barth, the philosophy of M. Heidegger, and the NT studies of R. Bultmann, under whom he received his doctorate at Marburg in 1929.
Fuchs' achievement lay in bringing the insights of Karl Barth, Rudolf Bultmann, and Martin Heidegger into fruitful conjunction.
He sought to bridge Barth's Calvinist emphasis on the revealed Word of God with Rudolf Bultmann's Lutheran emphasis on the nature of human existence before God by employing a phenomenology of language derived in part from Heidegger's later position, arguing that both human existence and the being of God are ultimately linguistic — made available in language – and that theology is thus properly "faith's doctrine of language" (Sprachlehre des Glaubens).
Conversely, the reality of God's love is verbalized in Jesus' word and deeds recorded in the Gospels and is thus preserved as language gain (Sprachgewinn).