Nikoloz Dadiani was a son of Giorgi Dadiani (died 1799), brother of Katsia II Dadiani, Prince of Mingrelia. His involvement in the politics and government of Mingrelia began in October 1804, when he became a member of the regency council for his underage relative, Levan V Dadiani, a grandson of Katsia II. The council was presided by Levan's mother, the dowager-princess Nino. A few months earlier, Mingrelia had become part of the Russian Empire as an autonomous principality. In 1805, Didi-Niko Dadini led a Mingrelian delegation to St. Petersburg sent to address the principality's territorial grievances with its neighbors. On his return, Dadiani found himself at odds with the dowager-princess, whom he accused of using the regency council to appease her own ambitions. After Levan V Dadiani became of age and Nino was sidelined from Mingrelia's government in 1811, Didi-Niko Dadiani's influence grew. The prince-regnant Levan had little interest in government affairs and day-to-day administrative routine and relied on Didi-Niko, who served as a chancellor (mdivanbegi) for years and, between 1804 and 1811, composed a new government code, known as dasturlama, to improve Mingrelia's governance.[1]
Didi-Niko Dadiani was a loyal subject to the Russian crown. As part of the Mingrelian forces ("militia"), he fought on the Russian side in the Russo-Turkish War (1806–1812), Russo-Persian War (1804–13), and Russo-Turkish War (1828–1829). He, further, aided the Russians in suppressing the western Georgian rebellions of 1810 and 1819–1820. He was made major-general and awarded the Order of St. Anna, First Class.[1]