Due to a car accident he missed most of his first-year seminary studies, and during that year he immersed himself in the works of Immanuel Kant and Søren Kierkegaard.

Jenson began reading historical-critical scholars like Hermann Gunkel and Sigmund Mowinckel, and as a result he became deeply interested in the biblical texts and in the theological significance of the Old Testament.

Though he had planned to write his dissertation on Bultmann, his supervisor, Peter Brunner [de], advised him to work on Karl Barth's doctrine of election.

The faculty of the religion department was uncomfortable with Jenson's theological liberalism, and his openness to biblical criticism and evolutionary biology was strongly condemned.

In The Knowledge of Things Hoped For (1969), he sought to integrate the traditions of European hermeneutics and English analytical philosophy, while also drawing on patristic and medieval theologians such as Origen and Thomas Aquinas.

At Oxford, Jenson also supervised the doctoral work of Colin Gunton, who went on to become one of Great Britain's most distinguished and influential systematic theologians.

He also began to engage deeply with patristic thought (especially with Gregory of Nyssa, Cyril of Alexandria, and Maximus the Confessor), which led him to develop a creative new proposal for trinitarian theology in The Triune Identity (1982).

After two decades of teaching at Lutheran Theological Seminary in Gettysburg, Jenson moved in 1988 to the religion department of St. Olaf College in Northfield, Minnesota.

[15] Jenson continued to teach at St. Olaf College until 1998, when he retired and took up a position as Senior Scholar for Research at the Center for Theological Inquiry in Princeton, New Jersey.