Little is definitively known about his life, but his surviving book Lives and Opinions of Eminent Philosophers is a principal source for the history of ancient Greek philosophy.

[17] In addition to the Lives, Diogenes refers to another work that he had written in verse on famous men, in various metres, which he called Epigrammata or Pammetros (Πάμμετρος).

Although it is at best an uncritical and unphilosophical compilation, its value, as giving us an insight into the private lives of the Greek sages, led Montaigne to write that he wished that instead of one Laërtius there had been a dozen.

[19] Diogenes divides his subjects into two "schools" which he describes as the Ionian/Ionic and the Italian/Italic; the division is somewhat dubious and appears to be drawn from the lost doxography of Sotion.

The work contains incidental remarks on many other philosophers, and there are useful accounts concerning Hegesias, Anniceris, and Theodorus (Cyrenaics);[20] Persaeus (Stoic);[21] and Metrodorus and Hermarchus (Epicureans).

From a table of contents in one of the manuscripts (manuscript P), this book is known to have continued with Zeno of Tarsus, Diogenes, Apollodorus, Boethus, Mnesarchus, Mnasagoras, Nestor, Basilides, Dardanus, Antipater, Heraclides, Sosigenes, Panaetius, Hecato, Posidonius, Athenodorus, another Athenodorus, Antipater, Arius, and Cornutus.

His chief authorities were Favorinus and Diocles of Magnesia, but his work also draws (either directly or indirectly) on books by Antisthenes of Rhodes, Alexander Polyhistor, and Demetrius of Magnesia, as well as works by Hippobotus, Aristippus, Panaetius, Apollodorus of Athens, Sosicrates, Satyrus, Sotion, Neanthes, Hermippus, Antigonus, Heraclides, Hieronymus, and Pamphila.

The first, Laertii Diogenis Vitae et sententiae eorum qui in philosophia probati fuerunt (Romae: Giorgo Lauer, 1472), printed the translation of Ambrogio Traversari (whose manuscript presentation copy to Cosimo de' Medici was dated February 8, 1433[31]) and was edited by Elio Francesco Marchese.

[33] The Greek/Latin edition of 1692 by Marcus Meibomius divided each of the ten books into paragraphs of equal length, and progressively numbered them, providing the system still in use today.

[42] Henricus Aristippus, the archdeacon of Catania, produced a Latin translation of Diogenes Laërtius's book in southern Italy in the late 1150s, which has since been lost or destroyed.

[43] Geremia da Montagnone used this translation as a source for his Compedium moralium notabilium (c. 1310) and an anonymous Italian author used it as a source for work entitled Liber de vita et moribus philosophorum (written c. 1317–1320), which reached international popularity in the Late Middle Ages.

[43] The Italian Renaissance scholar, painter, philosopher, and architect Leon Battista Alberti (1404–1472) borrowed from Traversari's translation of the Lives and Opinions of Eminent Philosophers in Book 2 of his Libri della famiglia[43] and modeled his own autobiography on Diogenes Laërtius's Life of Thales.

[45] Georg Wilhelm Friedrich Hegel (1770–1831) criticized Diogenes Laërtius for his lack of philosophical talent and categorized his work as nothing more than a compilation of previous writers' opinions.

[46] In the late twentieth and early twenty-first centuries, however, scholars have managed to partially redeem Diogenes Laertius's reputation as a writer by reading his book in a Hellenistic literary context.

"[47] Despite his importance to the history of western philosophy and the controversy surrounding him, according to Gian Mario Cao, Diogenes Laërtius has still not received adequate philological attention.

However, according to statements of the 14th-century monk Walter Burley in his De vita et moribus philosophorum, the text of Diogenes seems to have been much fuller than that which we now possess.

[51] Professor Brian Gregor suggests that readers will benefit from modern scholarly assistance while reading Diogenes' biographies, since they are "notoriously unreliable".