Dr. Werner Klän was born and baptized in Wuppertal, Germany, in 1952. Following his primary education, he studied theology in Oberursel and then theology and philosophy in Münster. Following successful completion of his university exams at both institutions, with a graduate study stipend intervening, he was ordained in November 1982 as a pastor in the Independent Evangelical-Lutheran Church (Selbständige Evangelisch-Lutherische Kirche [SELK]). He served from 1982-85 as an assistant professor at the Lutherische Theologische Hochschule and as the assistant pastor in the St. Johannes-Gemeinde, both in Oberursel. Following graduation from the Westfälischen Wilhlems-Universität Münster, he served from 1985-87 as pastor in the St. Thomas-Gemeinde in Münster. From 1987-1991 he was a research fellow at the Ostkirchen -Institut of the Westfälische Wilhlems-Universität Münster.

Klän then returned to serve at the institution with which he has been associated throughout most of his career, the Lutherische Theologische Hochschule in Oberursel. He served as a lecturer from 1990-93. In 1994 he completed his Habilitation dissertation and lecture in the faculty of church history at the Westfälische Wilhlems-Universität Münster. From 1993-96 he served as an interim professor of systematic theology at the Hochschule in Oberursel and then was appointed a full professor at the institution in 1996, a position he filled until being granted emeritus standing in March of last year. First holding the chair of Church History, he has served since 2003 as chair of the Systematics department. In addition, he has filled the position of rector on three occasions.

He has also filled professorships in Pretoria, South Africa, at the Lutheran Theological Seminary in Tshwane since 2008 and at the Department of Church History and Church Polity at the University of Pretoria since 2013. He has been a guest lecturer at many international universities and seminaries including Concordia Seminary, St. Louis. He has been occupied with research in the realm of confessional Lutheran churches and with "Third Reich" and post-war church history in general. More recently, he has been investigating the history of those churches throughout the last 50 years. From 1985 until 2006 he served as SELK speaker in ecumenical affairs. Since 2013 he has been a member of the Bilateral Dialogue Group of the International Lutheran Council and the Pontifical Council for Promoting Christian Unity (Roman Catholic Church).

His publications number over 150 books, chapters, essays, encyclopedia entries and book reviews in church history, Reformation and Lutheran history, theology of the Lutheran Confessions, systematic theology and ecumenical affairs.