In 1835, Wallin founded the Swedish Mission Society (Svenska Missionssällskapet), an organization for missions work among the Sámi people, together with Scottish Methodist missionary George Scott, industrialist Samuel Owen, Count Mathias Rosenblad, bishop Carl Fredrik af Wingård, and others.

But before he had even moved to Uppsala (seat of the bishopric), he died a sudden death in 1839, and was buried in Stockholm.

But he was weak in body, and this trait in combination with his strong work ethic may have caused stress on his health.

During the 20th century, the harsh Lutheranism associated with Wallin was being increasingly scorned in Sweden as being oppressive and guilt-stricken, and this trend in combination with increased secularization has diminished his reputation; today he is remembered for merely those hymns still in use in Swedish churches, the traditional Christmas hymn "Var hälsad, sköna morgonstund" among them.

Of his hymns still in use in Swedish hymnbooks today, a few have also been translated into English and published in hymnals such as the Lutheran Book of Worship.

These include – besides "Var hälsad, sköna morgonstund" ("All Hail to you, O blessed morn", translated to English by Ernst Olson) – "Du som fromma hjärtan vårdar" ("Christians, while on Earth abiding") and "Vi lovar Dig, O Store Gud" ("We worship you, O God of might"), as well as "Din klara sol går åter opp" as "Again, Thy Glorious Sun Doth Rise".

[8] His style is described as melancholic but ravishing, often dealing with death, with frequent references and quotes from the Bible.

This article contains content from the Owl Edition of Nordisk familjebok, a Swedish encyclopedia published between 1904 and 1926, now in the public domain.