Formation and Monastic Life
Before his tonsure Leo Nagolkin worked for a merchant, and through frequent business travel he gained experience in dealing with people of diverse backgrounds. He entered the Optina Monastery in 1797, during the community's period of revival, and after about two years transferred to White Bluff Monastery under Hieromonk Basil (Kiskin), where he trained in obedience, patience, and various external labors.
In 1801 Fr. Basil tonsured him a monk with the name Leonid, ordaining him deacon on December 22 and priest on December 24 of that year. At Cholnsk Monastery he met Schemamonk Theodore, a disciple of St. Paisius Velichkovsky, who became his spiritual mentor and through whom he received the hesychast tradition that would shape his own practice.
In 1804 Bishop Dorotheus appointed Leonid igumen of White Bluff. He resigned this office in 1808 to receive the great schema, taking the name Leo, together with Theodore and Cleopas. The three moved between monasteries over the following years — New Lake in 1809, Palei Island Hermitage, and the All Saints Skete of Valaam Monastery in 1812. After Cleopas died in 1816, Leonid and Theodore moved to the Monastery of St. Alexander of Svir, where Theodore died on April 7, 1822.
Eldership at Optina
Leonid arrived at the Optina Monastery in April 1829 with six disciples and introduced there the practice of eldership, having received the teaching from his mentor Fr. Theodore. His disciple Macarius followed in 1834, and through him the tradition of eldership was established at the monastery in a systematic and enduring form.
Leonid's ministry drew large numbers of visitors seeking spiritual counsel. Between 1835 and 1836 some monks complained to the bishop about the disruptions his many visitors caused, and in 1841 he became entangled in convent disputes involving expelled nuns, a matter later resolved through the intervention of Metropolitan Philaret.
Repose and Glorification
Leonid's health declined in September 1841. He received Holy Unction on September 15 and Holy Communion on September 28, and reposed on the evening of October 11, 1841. He was buried near the church of the Entrance of the Theotokos, opposite the chapel of St. Nicholas.
The Russian Orthodox Church Outside Russia glorified Leonid together with all the Optina Elders in 1990. The Patriarchate of Moscow authorized his local veneration on June 13, 1996, and proclaimed his universal glorification on August 7, 2000. His feast is kept on October 11 (October 24 New Style).