This paper investigates the life and scholarship of Franz Delitzsch (1813–1890) with the aim of demonstrating his relevance for contemporary Old Testament scholars. This is achieved by concentrating on Delitzsch’s work on the book of Isaiah and his engagement with a contested issue of his own day—namely, the question of Isaiah’s authorship and unity. Contrary to the common depiction of Delitzsch as one who ultimately capitulated to critical viewpoints in the fourth and final edition of his Isaiah commentary, this essay suggests that the reality is more complex; instead, Delitzsch should be understood as presenting an innovative solution to the problem of Isaianic unity and authorship. Through his careful blend of confessional convictions and critical perspectives in relation to this one particular issue, Delitzsch exhibits a model of biblical scholarship that is of interest and value for evangelical scholars today. To build this case, the essay first offers a broad sketch of Delitzsch’s life and contributions, as well as his exegetical approach. Next, the context for his work on Isaiah is outlined and attention is given to the alleged position changes reflected in the fourth edition of his commentary. The final section of the essay illustrates the true scope and significance of Delitzsch’s position changes based on a comparative study of his earlier and later Isaiah commentaries.