He was probably born in Hof in Upper Franconia, Bavaria, around 1485. He studied at the University of Leipzig and obtained a masters degree at Wittenburg University in 1523 and became a monk. Although a monk, he was an advocate of the Protestant Reformation and a disciple of Martin Luther. He was Probst of the cloister at Steterburg from 1519 until July 1522 when he was appointed a master in the St. Katherine and Egidien School in Braunschweig. He wrote in 1523 for Allein Gott in der Höh sei Ehr, adapted by Luther in 1525, a German paraphrase of the Latin Gloria. Decius's version was first sung on Easter Day at Braunschweig on 5 April 1523. Decius's Low German version first appeared in print in Gesang Buch by Joachim Sluter, printed in 1525.
In 1526, Decius became preacher at the Church of St. Nicholas in Stettin at the same time as Paulus von Rhode was appointed preacher at St. Jacob's in Stettin. In 1535 he became pastor of St. Nicholas and died there in March 1541 after a suspected poisoning. Shortly before his death he wrote the hymn "O Lamm Gottes, unschuldig" (O Lamb of God, innocent) sung on a tune from the 13th century. Decius's version was first published in Anton Cornivus's Christliche Kirchen-Ordnung in 1542. Johann Sebastian Bach used it as a cantus firmus in the opening chorus of his St Matthew Passion. It was translated into English by Arthur Tozer Russell in the 19th century.
- "Nikolaus Decius (Hymn-Writer, Composer)". Bach Cantatas.com. Retrieved 3 March 2012.
- Fornacon, Siegfried (1957). "Decius, Nikolaus. In: Neue Deutsche Biographie (NDB).". Band 3, Duncker & Humblot, Berlin. p. 542.
- McKim, LindaJo K. (1 June 1993). The Presbyterian hymnal companion. Westminster John Knox Press. p. 76. ISBN 978-0-664-25180-2. Retrieved 3 April 2012.
- Goltz, Georg Friedrich Gottlob (1843). Ausführliche erklärung einiger der vorzüglichsten evangelischen kirchenlieder für schule und haus. T. Scherk. p. 201. Retrieved 3 April 2012.
- Leahy, Anne (16 October 2011). J. S. Bach's "Leipzig" Chorale Preludes: Music, Text, Theology. Scarecrow Press. p. 179. ISBN 978-0-8108-8181-5. Retrieved 3 April 2012.
- Glover, Raymond F. (February 1995). The Hymnal 1982 companion. Church Publishing, Inc. p. 789. ISBN 978-0-89869-143-6. Retrieved 3 April 2012.