Due to his high profile as a Soviet dissident writer, social critic, and activist during his later life, Likhachev was often referred to as "Russia's conscience".

"[1] For his election to the "Cosmic Academy", Likhachev had presented a short report, in which he poked fun at the new spelling rules of 1918 and urged that they be "reformed" by restoring the banned letter "Yat".

After his arrest, Likhachev was confronted with the paper by a Soviet secret police interrogator, who screamed, "What do you mean by language reform?

"[1] After nine months in jail, the young scientist was unlawfully exiled without trial and spent five years in the USSR's first concentration camp, located on the Solovetsky Islands in the White Sea.

At the camp, hard work, poor living conditions and illness dramatically damaged Likhachev's health, but he survived.

Whilst on the islands, for some period of time Dmitry Likhachev worked as a member of the Criminological Cabinet, organizing a labor colony for teenagers and saving them from death caused by hunger, drugs, and cold.

In a 1987 interview with David Remnick, Likhachev recalled the events of that night and concluded, "The executioner is older than me, and he is still alive.

In 1936, thanks to petitions by the president of the Academy of Sciences, Aleksandr Karpinsky, Dmitry Likhachev's criminal record was cleared.

Old Russian literature, which at that time did not receive much academic attention, became the main scientific interest of Dmitry Likhachev who, by the beginning of the 1940s, was one of the most renowned specialists in this sphere.

He described his experience in a story, full of harsh details, exposing different types of people and their heroic or appalling behavior when faced with starvation and death.

In 1942, completely exhausted by hunger and cold, Dmitry Likhachev started to gather materials on medieval poetry and soon published the book Defense of the Old Russian Cities.

In 1947 Dmitry Likhachev received his Doctorate in Philology, having presented his thesis "Essays on the History of Annalistic Literary Forms of the 11th–16th Centuries".

1950 marked the publication of Likhachev's two-volume edition containing unique, important literary works translated into the modern Russian language: The Primary Chronicle, a history of Kievan Rus' from the 9th to the 12th centuries, and The Lay of the Host of Igor, an account based on a failed raid by Prince Igor Svyatoslavich of Novgorod-Seversk against the Cumans in 1185.

Thanks to Likhachev many monuments were saved, including Marina Tsvetaeva's flat in Moscow, the Nevsky Prospect in Leningrad (which was supposed to be turned into a shopping street) and Aleksandr's Garden.

The scientist also participated in the preservation of national minorities in danger of dying out while aiding the return to Russia of émigré public and cultural figures.

Inspired by the works of Vladimir Vernadsky, Dmitry Likhachev suggested the idea of a “homosphere”- a human sphere of the Earth.

His original contribution to general science was also the development of a new discipline called the ecology of culture, which was defined as an essential sphere of human life.

In his 1980s and 1990s, he became more of a public figure, serving as an informal advisor to St. Petersburg Mayor Anatoly Sobchak and Russian President Boris Yeltsin.