"Amedeus comes" donated property to Saint-Jean de Maurienne, for the soul of "patris sui Uberti comtis", with the consent of "Gisla matre et fratribus eius Guillelmo atque Umberto", by charter dated 21 Oct 1104, witnessed by "Odo de Camera et frater eius Amedeus, Esmio de Camera et frater eius Bernardus, Aymo de Bocsosello, Guillelmus de Rossilione". "Amedeus…comes et fratres mei, unacum genitrice nostra Gisla" donated property to the church of Belley, for the soul of "patris nostri Humberti comitis", by undated charter.
He succeeded in 1109 as AMEDEE III Comte de Maurienne et de Savoie. "Amedeus…comes et fratres mei, unacum genitrice nostra Gisla" donated property to the church of Belley "per nostros advocatos…comitem Aimonem Genevensem et Widonem de Mirabello", for the soul of "patris nostri Humberti comitis", by undated charter. The emperor recognised his title as Count of the Holy Roman Empire in 1111. Comte Amedée arranged the marriage of his sister to Louis VI King of France, consolidating the close relations established by his father with France.
Lay-abbot of Saint-Maurice d'Agaune, until 1116. "Guido Viennensis archiepiscopus" (who was his maternal uncle) addressed a letter to "nepoti suo Amedeo comiti" dated . "Amedeus filius quondam Humberti comitis" confirmed the possessions of the abbey of Santa Maria di Pinerolo by charter dated 1 Mar 1131, witnessed by "Humbertus de Buzosel et Aymo frater eius, Villelmus de Camera…". He recovered the county of Turin, lost by his father. "Comes Amedeus…cum uxore sua Adeleida comitissa" confirmed the rights of the monastery of "S. Justi in villa Volveria" by charter dated 27 Jul 1134, witnessed by "Umbertus de Bocsosello, Aimo de Brianzone…". "A. comes et marchio cum uxore sua M." donated property to the monastery of Ripalta, with the support of "eorum filio Umberto", by charter dated 9 Jan 1137. "Palatinus Comes Amedeus" donated property to the monastery of Locedio "in terra Willelmi Marchionis fratris sui" [his uterine brother] by charter dated 30 Jul 1137. "Amedeus comes et marchio" donated revenue from Conflens to the archbishop of Tarantasia by charter dated 28 Feb 1139. "Dominus Amedeus comes et marchio et frater eius Raynaldus" granted rights to the archbishop of Tarantasia, with the consent of "Aymone vicecomite, fratribus suis Gunterio, Willienco, Aymerico", by charter dated to . The first known use of the white cross on a red background as the arms of the House of Savoy was in a charter dated 1143. "Amedeus comes et marchio et Maies comitissa uxor eius et Umbertus eorum filius" donated property to the monastery of Saint-Maurice by charter dated 30 Mar 1143. "Amedeus comes et marchio" confirmed donations to Saint-Sulpice en Bugey, for the soul of "filii mei Humberti", by charter dated to , which also names "uxore mea Matildi", confirmed by "Aalasia comitissa de Bello Joco…cum filio meo Guichardo". "Amedeus comes et marchio et Majes comitissa uxor eius et Umbertus eorum filius" confirmed the rights of the monastery of Saint-Maurice d´Agaune by charter dated 30 Mar 1148.
He accompanied his nephew Louis VII King of France on crusade but died in Cyprus. The Continuator of Sigebert records that "Amadeus comes Maurianensis" died "in Cipro insula" in 1148. 1