Baryatinsky entered the school of the ensigns of the Guard in his seventeenth year and, on November 8, 1833, received his commission of cornet in the Life Guards of the future TsarAlexander II. In 1835, he served with great gallantry in the Caucasus, and on his return to St.Petersburg was rewarded with a golden sword for valour. On January 1, 1836, he was attached to the suite of Alexander, and in 1845 was again ordered off to the Caucasus and again most brilliantly distinguished himself, especially in the attack on Shamil's stronghold, for which he received the Order of St. George. In 1846, he assisted Field Marshal Ivan Paskevich to suppress the Kraków Uprising. From 1848 to 1856 he took a leading part in all the chief military events in the Caucasus, his most notable exploits being his victory at Mezeninsk in 1850 and his operations against Shamil in Chechnya. His energetic and at the same time systematic tactics inaugurated a new era of mountain warfare. On January 6, 1853, he was appointed adjutant general and, on July 5 of the same year, chief of staff. In 1854, he took part in the brilliant Kurbsk Dere campaign. On January 1, 1856, he became commander-in-chief of the Caucasian army, and, subsequently, governor of the Caucasus. As an administrator, he showed himself fully worthy of his high reputation. Within three years of his appointment, the whole of the eastern Caucasus was subdued and the long elusive Shamil was taken captive. Baryatinsky also conquered many of the tribes of the western Caucasus dwelling between the rivers of Laba and Belaya. 
By the early 1860s, his health had seriously deteriorated, and on December 6, 1862, he was relieved of his post at his own request. He spent the last days of his life abroad and died in Geneva, after forty-eight years of active service.