Parnaoz's active involvement in the politics of his country came with the accession of his half-brother, George XII, to the throne of Kartli and Kakheti after the death of Heraclius II in 1798. George reversed the rule of succession approved in 1791 by Heraclius under the influence of Queen Darejan, requiring the king's successor to pass the throne not to his offspring, but to his eldest brother. This would have made Parnaoz the 6th in the line of succession, behind George and his elder brothers, Iulon, Vakhtang, Mirian, and Alexander. Instead, the new monarch, having renewed quest for Russian protection, obtained from Paul I of Russia recognition of his son, David, as heir-apparent on 18 April 1799.^[1] This gave rise to a dynastic dispute, in which Parnaoz stood by Iulon's side.^[2][3]

By July 1800, the crisis had taken on the characteristics of a military conflict. Parnaoz joined his brothers, Iulon and Vakhtang, in blocking the roads to the capital city of Tbilisi in an attempt to rescue their mother, Queen Dowager Darejan, who had been forced by George XII into confinement at her own palace in Avlabari. Parnaoz threatened Gori and the king ordered Prince Otar Amilakhvari to defend the town at all cost. The arrival of additional Russian troops under Major-General Vasily Gulyakov in September 1800 in Tbilisi made George XII's position relatively secure and the rebellious princes withdrew to the provinces. Parnaoz took control of the important fortress of Surami and began to fortify it, while another of his brothers, the bellicose Prince Alexander, fled to Dagestan to rally the Avars for his cause.^[4][5]

After the death of George XII in December 1800 the Russians prevented his heir David from acceding to the throne and went ahead with the outright annexation of Georgia to the Russian Empire. The Russian commander in Georgia, General Ivan Lazarev, requested that all the members of the royal house should assemble and remain in Tbilisi. In April 1801 Iulon and Parnaoz defied the order and fled to western Georgia, to the court of their sisterly nephew, King Solomon II of Imereti,^[6] who had upheld Iulon's claim to the throne of Kartli and Kakheti.^[7]

After a series of attempts to induce the Georgians to rise against the Russian rule, Iulon and Parnaoz eventually crossed, in June 1804, into Kartli, where the Georgian and Ossetian peasants had revolted. The princes failed to make their way to join the rebels and fell back to Imereti. A Russian detachment, commanded by Captain Novitsky and guided by the loyal Georgian prince Giorgi Amirejibi, hurried from Tskhinvali and surprised Iulon's sleeping men at the Imeretian border.^[4] In a brief skirmish on 24 June 1804, Iulon was captured, barely escaping death, and sent in custody to Tbilisi. Parnaoz fled to the Iranian-controlled territory,^[8] but soon returned to reignite the revolt among the Georgian highlanders and the Ossetians, living on both sides of the Greater Caucasus crest.^[9]

Initial successes of the rebels were reversed by the resolute action of Major General Pyotr Nesvetayev in September 1804. Nesvetayev foiled Parnaoz's attempt to prevent the fall of Stepantsminda to the Russians, defeated his forces at Sioni, and, pursuing the retreating prince down to the Terek valley, quickly seized his main base at Ananuri. Parnaoz, with his 30 followers, including the young prince Alexander Chavchavadze, the future poet and general of the Russian army,^[10] attempted to fight his way to Erivan, but was apprehended in October 1804, while fording the Kura at Demurchasaly, some 43 km south of Tbilisi, by a Russian "flying detachment" commanded by his wife's relative, Brigadier Prince Tamaz Orbeliani.^[9]

Prince Pavel Tsitsianov, the Russian commander in Georgia, captured Parnaoz and Iulon on 4 April 1805; he had Parnaoz deported to Voronezh and Iulon sent to Tula.^[8] Accompanied by his wife and four daughters, Parnaoz later obtained a permission to move to St. Petersburg, where he settled permanently. During his exile in Voronezh, he went blind translating into Georgian the works of Jean-Jacques Rousseau. Parnaoz was also a poet of some talent. His best known writings, particularly, his poem "All of you, remember bygone times" (იგონეთ ყოველთა დრონი წინარე), were imbued with the language of lament for his lost kingdom.^[11] He died in 1852, having outlived his wife and four of his six children. He was buried at the Church of St. Theodore, the Alexander Nevsky Lavra.^[12][13]

Prince Parnaoz married in 1795 Anna (1777 – 25 May 1850), daughter of Prince George, the last Duke of Ksani. She was the Dame of the Lesser Cross of the Order of St. Catherine (1841), died at St. Petersburg, and was buried at the Alexander Nevsky Lavra. The couple had one son and five daughters:^[12][13]

• Prince David. He died in infancy.
• Princess Salome (1797 – 20 August 1860), Maid of Honor to the Empress of Russia. She died unmarried at St. Petersburg.
• Princess Sophio (1798 – ?). She died very young.
• Princess Elene (1799 – 7 July 1867), Maid of Honor to the Empress of Russia. She died unmarried at Tsarskoye Selo.
• Princess Elisabed (4 October 1800 – 21 December 1819). She died unmarried at St. Petersburg and was buried at the Alexander Nevsky Lavra.
• Princess Nino (28 September 1802 – 1 September 1828), Dame of the Lesser Cross of the Order of St. Catherine (1833). She married in 1822, as his first wife, Colonel Prince Alexander Dadiani (1800 – 1865) and had one son, Nikolay (1824 – 1829). She is buried at the Alexander Nevsky Lavra.