Most likely he went to some benedictine monastic school in Istria. While a youth he lived in France and Spain and got his philosophical and philological knowledge in famous Bernard's and Theodoric's school in Chartres and in Paris between 1130 and 1135. Theodoric (Thierry) of Chartres (circa 1085 - circa 1150) was younger Bernard's brother and a Platonist philosopher. Among his disciples was also John of Salisbury (Johannes de Saresberia Parvus) (circa 1110/1115-1180). Theodoric taught in Paris for some period until 1141 and then he returned to Chartres.
After his studies Herman went with his classmate Robert of Ketton to Arabic countries in the East. At Constantinople and Damascus he recognized an Arabic science of that period. Circa 1138 he returned to Europe and he took an active part in Spain and southern France. A huge part of his work remained anonymous.
Herman's first known translation of the sixth book of an astrological treatise Liber sextus astronomie of Jewish writer Saul ben ibn Bishr was published in Spain in 1138 under his translated title Zaelis fatidica (Prophesy). Saul ben ibn Bishr had been writing under the Greek astrological tradition. Bishr's first five books were preserved in the translation of John of Seville (Johannes Hispanus) (circa 1090- circa 1150). A text of the sixth book is divided into seven treatises, which deal with three thematic topics. The first topic is about different changes from the world, the second about the changes from the air and the third about inequalities among people, which originate on account of inevitable various influences. This work contains a treatises about planets, a divinations from their retrograde movements and their mutual positions, and a divinations, based on the movements of comets.
Circa 1140 he translated into Latin astronomical work of Abu Ma'shar Kitab al-madkhal ila ilm ahkam al nujum (Introduction to the astronomy). This translation was published several times under the title Liber introductorius in astronomiam Albumasaris, Abalachii (Augusta Vindelicorum, Augsburg 1489; Venice 1495 and 1506). This work was first separately translated into Latin by John of Seville in 1133 and it contains problems from Greek philosophy, Arabic astronomy and Eastern astrology. A large part of Herman's translation was copied into Roger of Hereford's Book of Astronomical Judgements.
Within this time Herman most likely from Arabic translations had translated Muhammad al-Khwarizmi's astronomical tables (zij), which were also translated in 1126 by Adelard of Bath, and Euclid's Geometrical Elements (Euclidis geometria (Elementa)), also translated by Adelard at that time. Circa 1142 Herman began in León to translate the Qur'an into Latin. He also translated two treatises De generatione Muhamet et nutritura eius and Doctrina Muhamet. He continued with unfinished Qur'an. This translation was completed by his English friend Robert of Chester de Retin. The original manuscript of a translation was found in Constantinople by Ivan Stay. After this manuscript and revised Latin translation of the Qur'an by Peter the Venerable (1094-1156) in 1543 Theodor Bibliander (1504-1564) published his edition of the Qur'an in Basel. In this edition both Herman's translations of mentioned treatises about islam were announced together with Martin Luther's Preface.
His most important work is a Latin translation of Claudius Ptolemy's work Planisphaerium. He translated it from an Arabic translation from Greek jointly with commentaries of Maslam ibn Ahmed al-Majriti, who worked in Cordoba in the 10th century. Western European scholastics became aware of Ptolemy's astronomical views via this translation, published in Toulouse in 1143. This translation was for a long time believed to be the only trace of an original Ptolemy's work. Later another preserved Arabic translation was found in Istanbul.
Herman also translated Ptolemy's work The canons. For long many thought that Ptolemy was translated by German Herman Contractus and not by Herman of Carinthia.
His original philosophical work, which became known to us, was De essentiis (On essences). In this work Herman deals with five Aristotelian categories (causa, motus, spatium, tempus, habitudo). He started to write this treatise in 1143 in Toulouse and he completed it the same year in Beziers. In 1982 this book was reprinted in Germany.
Some other works are believed to be Herman's: a meteorological Liber imbrium (A book about precipitations) (1140 to 1141), astrological De indagatione cordis (About heart researches) (after 1140) , mathematical and astronomical De mensura, De utilitatibus astrolabii, De compositione et usu astrolabii (before 1143), and so on. In a text of De indagatione cordis there are many names of scientists and scholars, of which work Herman knew and used: Abu Mas'har (787-886), Saul ben ibn Bishr, Aomar Tiberia, Abu al-Kindi (circa 800-873), 8th century Jewish astrologer Al Batrig Mashallah (Messahalla), Hermes and Dorotheos from Sidon. The whole text in Latin original was critically published by Sheila Low-Beer in her doctoral dissertation Herman of Carinthia: The Liber imbriam, The Fatidica and the De indagatione Cordis, The City University of New York. Many medieval authors refer to Herman's work, for instance Albert the Great (Albert von Bollstädt, Albertus Magnus), instructor to Thomas Aquinas, in his work Speculum astronomiae.
Among Adelard of Bath (1075-1160), John of Seville, Gerard of Cremona (1114-1187) and Plato of Tivoli (1134-1145) Herman is the most important translator of Arabic astronomical works in 12th century and populariser of Arabic culture in Europe. The influence of his translations on the development of medieval European astronomy was specially large.