In 1879 he succeeded Carl Wilhelm Böttiger to the seat 8 of the Swedish Academy, and moved the year after to Stockholm, where he became literary reviewer for the Post- och Inrikes Tidningar, and in 1886 also for the magazine Vårt Land.

The former work resulted in Svenska Akademiens ordlista (The Swedish Academy's dictionary), where the modern spelling was represented, in spite of af Wirséns's opposition.

In December 1883, he was appointed member of The Hymn Book committee of the Church of Sweden, which had the task of "preparing, with discretion, a new proposal for hymnbook".

af Wirsen's conservative views and an abundant publication of his literary criticism made him well-known but also provoked opposition, sometimes in harsh words, by his opponents, who represented new ideas with spelling reform and a freer style.

The calling of the poet is a priesthood of light, he should in poetry reveal a higher world of purity and peace..." As a critic, Wirsén found a hearing among many educated men, but not much connection with the young literature, and he has become notorious for his many negative reviews of August Strindberg, Verner von Heidenstam, Selma Lagerlöf, Henrik Ibsen and many others.