Plutarch was born to a prominent family in the small town of Chaeronea, about 80 kilometres (50 mi) east of Delphi, in the Greek region of Boeotia. His family was wealthy. The name of Plutarch's father has not been preserved, but based on the common Greek custom of repeating a name in alternate generations, it was probably Nikarchus (Nίκαρχoς). The name of Plutarch's grandfather was Lamprias, as he attested in Moralia and in his Life of Antony.
His brothers, Timon and Lamprias, are frequently mentioned in his essays and dialogues, which speak of Timon in particular in the most affectionate terms. Rualdus, in his 1624 work Life of Plutarchus, recovered the name of Plutarch's wife, Timoxena, from internal evidence afforded by his writings. A letter is still extant, addressed by Plutarch to his wife, bidding her not to grieve too much at the death of their two-year-old daughter, who was named Timoxena after her mother. He hinted at a belief in reincarnation in that letter of consolation.
The exact number of his sons is not certain, although two of them, Autobulus and the second Plutarch, are often mentioned. Plutarch's treatise De animae procreatione in Timaeo is dedicated to them, and the marriage of his son Autobulus is the occasion of one of the dinner parties recorded in the "Table Talk". Another person,
Soklarus, is spoken of in terms which seem to imply that he was Plutarch's son, but this is nowhere definitely stated. His treatise on marriage questions, addressed to Eurydice and
Pollianus, seems to speak of the latter as having been recently an inmate of his house, but without any clear evidence on whether she was his daughter or not.
Plutarch was the uncle of Sextus of Chaeronea, who was one of the teachers of Marcus Aurelius, and who may have been the same person as the philosopher Sextus Empiricus.
Plutarch studied mathematics and philosophy at the Academy of Athens under Ammonius from 66 to 67.
At some point, Plutarch received Roman citizenship. As evidenced by his new name, Lucius Mestrius Plutarchus, his sponsor for citizenship was
Lucius Mestrius Florus, a Roman of consular status whom Plutarch also used as a historical source for his Life of Otho.
He lived most of his life at Chaeronea, and was initiated into the mysteries of the Greek god Apollo. For many years Plutarch served as one of the two priests at the temple of Apollo at Delphi, the site of the famous Delphic Oracle, twenty miles from his home. He probably took part in the Eleusinian Mysteries. By his writings and lectures Plutarch became a celebrity in the Roman Empire, yet he continued to reside where he was born, and actively participated in local affairs, even serving as mayor. At his country estate, guests from all over the empire congregated for serious conversation, presided over by Plutarch in his marble chair. Many of these dialogues were recorded and published, and the 78 essays and other works which have survived are now known collectively as the Moralia. 
Work as magistrate and ambassador
In addition to his duties as a priest of the Delphic temple, Plutarch was also a magistrate at Chaeronea and he represented his home town on various missions to foreign countries during his early adult years. Plutarch held the office of archon in his native municipality, probably only an annual one which he likely served more than once. He busied himself with all the little matters of the town and undertook the humblest of duties.
The Suda, a medieval Greek encyclopedia, states that Emperor Trajan made Plutarch procurator of Illyria. However, most historians consider this unlikely, since Illyria was not a procuratorial province, and Plutarch probably did not speak Illyrian.
According to the 8th/9th-century historian George Syncellus, late in Plutarch's life, Emperor Hadrian appointed him nominal procurator of Achaea – which entitled him to wear the vestments and ornaments of a consul.
Late period: Priest at Delphi
Portrait of a philosopher and Hermaic stele at Delphi Museum
Plutarch spent the last thirty years of his life serving as a priest in Delphi. He thus connected part of his literary work with the sanctuary of Apollo, the processes of oracle-giving and the personalities who lived or traveled there. One of his most important works is the "Why Pythia does not give oracles in verse" (Moralia 11) ( "Περὶ τοῦ μὴ χρᾶν ἔμμετρα νῦν τὴν Πυθίαν"). Even more important is the dialogue "On the E in Delphi" ("Περὶ τοῦ Εἶ τοῦ ἐν Δελφοῖς"), which features Ammonius, a Platonic philosopher and teacher of Plutarch, and Lambrias, Plutarch's brother. According to Ammonius, the letter E written on the temple of Apollo in Delphi originated from the following fact: the wise men of antiquity, whose maxims were also written on the walls of the vestibule of the temple, were not seven but actually five: Chilon, Solon, Thales, Bias and Pittakos. However, the tyrants Cleobulos and Periandros used their political power in order to be incorporated in the list. Thus, the E, which corresponds to number 5, constituted an acknowledgment that the Delphic maxims actually originated from the five real wise men.
The portrait of a philosopher exhibited at the exit of the Archaeological Museum of Delphi, dating to the 2nd century AD, had been in the past identified with Plutarch. The man, although bearded, is depicted at a relatively young age. His hair and beard are rendered in coarse volumes and thin incisions. The gaze is deep, due to the heavy eyelids and the incised pupils. The portrait is no longer thought to represent Plutarch.
But a fragmentary hermaic stele next to the portrait probably did once bear a portrait of Plutarch, since it is inscribed, "The Delphians along with the Chaeroneans dedicated this to Plutarch, following the precepts of the Amphictyony" ("Δελφοὶ Χαιρωνεῦσιν ὁμοῦ Πλούταρχον ἔθηκαν | τοῖς Ἀμφικτυόνων δόγμασι πειθόμενοι" Syll.3 843=CID 4, no. 151).