His life is only documented briefly for two periods. Like many composers who originated in the modern-day Low Countries, he spent time in Italy, and sang in the papal chapel in 1433. His presence is also recorded in the Burgundian court chapel, where he was employed as a singer from 1441 to 1454.
Only one piece of music is securely attributed to him, a song entitled Comment porray. The manuscript containing it, formerly in the Strasbourg Bibliothèque Municipale, was destroyed on August 24, 1870, during the Siege of Strasbourg in the Franco-Prussian War.
It is not known if Liebert was related to Reginaldus Libert (Liebert), another Burgundian composer who was one of the first to use fauxbourdon in a setting of the Ordinary of the Mass. It is also possible that Clement Liebert is the same as a J. de Climen, a composer of around 1430, to whom a two-voice canon was attributed in a manuscript formerly from a Strasbourg library, now destroyed.
- David Fallows: "Clement Liebert", Grove Music Online, ed. L. Macy (Accessed May 16, 2007), (subscription access)
- Stanley Boorman, et al. "Sources, MS, §VII." Grove Music Online, ed. L. Macy (Accessed February 19, 2009) (subscription access)
- Tom R. Ward: "J. de Climen", Grove Music Online, ed. L. Macy (Accessed May 16, 2007), (subscription access)
- Gustave Reese, Music in the Renaissance. New York, W.W. Norton & Co., 1954. ISBN 0-393-09530-4
- Fallows, Grove online
- Grove online, Sources, MS, §VII
- Tom R. Ward, Grove online