Beria was born in Merkheuli, near Sukhumi, in the Sukhum Okrug of the Kutais Governorate (now Gulripshi District, Abkhazia, Georgia, then part of the Russian Empire). He was from the Mingrelian subethnic group of Georgians and grew up in a Georgian Orthodox family. Beria's mother, Marta Jaqeli (1868–1955), was deeply religious and church-going (she spent much time in church and died in a church building); she was previously married and widowed before marrying Beria's father, Pavel Khukhaevich Beria (1872–1922), a landowner from Abkhazia. He also had a brother (name unknown), and a deaf sister named Anna.

In his autobiography, Lavrentiy Beria mentioned only his sister and his niece, implying that his brother (or any other siblings) either was dead or had no relationship with Beria after he left Merkheuli. Beria attended a technical school in Sukhumi, and joined the Bolsheviks in March 1917 while a student in the Baku Polytechnicum (subsequently known as the Azerbaijan State Oil Academy). As a student, Beria distinguished himself in mathematics and the sciences. The Polytechnicum's curriculum concentrated on the petroleum industry.

In 1919, at the age of twenty, Beria started his career in state security when the security Service of the Azerbaijan Democratic Republic hired him while still a student at the Polytechnicum. In 1920 or 1921 (accounts vary) Beria joined the Cheka, the original Bolshevik secret police. At that time, a Bolshevik revolt took place in the Menshevik-controlled Democratic Republic of Georgia, and the Red Army subsequently invaded. The Cheka became heavily involved in the conflict, which resulted in the defeat of the Mensheviks and the formation of the Georgian SSR. By 1922, Beria was deputy head of the Georgian branch of Cheka's successor, the OGPU.

Beria also worked for the anti-Bolshevik Mussavatists in Baku. After the Red Army captured the city on 28 April 1920, Beria was saved from execution because there was not enough time to arrange his shooting and replacement, and Sergei Kirov possibly intervened. While in prison, he formed a connection with Nina Gegechkori (1905–10 June 1991) his cellmate's niece, and they eloped on a train. She was 17, a trained scientist from an aristocratic family.

In 1924 he led the repression of a Georgian nationalist uprising, after which up to 10,000 people were executed. For this display of "Bolshevik ruthlessness," Beria was appointed head of the "secret-political division" of the Transcaucasian OGPU and was awarded the Order of the Red Banner.

In 1926 Beria became head of the Georgian OGPU; Sergo Ordzhonikidze, head of the Transcaucasian party, introduced him to fellow-Georgian Joseph Stalin. As a result, Beria became an ally in Stalin's rise to power. During his years at the helm of the Georgian OGPU, Beria effectively destroyed the intelligence networks that Turkey and Iran had developed in the Soviet Caucasus, while successfully penetrating the governments of these countries with his agents. He also took over Stalin's holiday security.

Beria was appointed Secretary of the Communist Party in Georgia in 1931, and for the whole Transcaucasian region in 1932. He became a member of the Central Committee of the Communist Party of the Soviet Union in 1934. During this time, he began to attack fellow members of the Georgian Communist Party, particularly Gaioz Devdariani, who served as Minister of Education of the Georgian SSR. Beria ordered the executions of Devdariani's brothers George and Shalva, who held important positions in the Cheka and the Communist Party respectively.

By 1935 Beria had become one of Stalin's most trusted subordinates. He cemented his place in Stalin's entourage with a lengthy oration titled, "On the History of the Bolshevik Organisations in Transcaucasia" (later published as a book), which emphasized Stalin's role. When Stalin's purge of the Communist Party and government began in 1934 after the assassination of Leningrad party boss Sergei Kirov (1 December 1934), Beria ran the purges in Transcaucasia. He used the opportunity to settle many old scores in the politically turbulent Transcaucasian republics.

In June 1937 he said in a speech, "Let our enemies know that anyone who attempts to raise a hand against the will of our people, against the will of the party of Lenin and Stalin, will be mercilessly crushed and destroyed."

In August 1938, Stalin brought Beria to Moscow as deputy head of the People's Commissariat for Internal Affairs (NKVD), the ministry which oversaw the state security and police forces. Under Nikolai Yezhov, the NKVD carried out the Great Purge: the imprisonment or execution of millions of people throughout the Soviet Union as alleged "enemies of the people." By 1938, however, the oppression had become so extensive that it was damaging the infrastructure, economy and even the armed forces of the Soviet state, prompting Stalin to wind the purge down. Stalin had thoughts to appoint Lazar Kaganovich as head of the NKVD, but chose Beria probably because he was a professional secret policeman. In September, Beria was appointed head of the Main Administration of State Security (GUGB) of the NKVD, and in November he succeeded Yezhov as NKVD head (Yezhov was executed in 1940). The NKVD was purged next, with half its personnel replaced by Beria loyalists, many of them from the Caucasus. He reportedly won Stalin's favour in the early 1930s after faking a conspiracy to assassinate the Soviet leader that he then claimed to have foiled. In 1938 Stalin rewarded Beria's loyalty by making him head of the NKVD. One account says Beria personally strangled his predecessor, Nikolai Yezhov.

In March 1939, Beria became a candidate member of the Communist Party's Politburo. Although he did not become a full member until 1946, he was already one of the senior Leaders of the Soviet state. In 1941 Beria was made a Commissar General of State Security, the highest quasi-military rank within the Soviet police system of that time, effectively comparable to a Marshal of the Soviet Union.

From October 1940 to February 1942, the NKVD under Beria carried out a new purge of the Red Army and related industries. In February 1941, Beria became Deputy Chairman of the Council of People's Commissars, and in June, following Nazi Germany's invasion of the Soviet Union, he became a member of the State Defense Committee (GKO). During World War II, he took on major domestic responsibilities and mobilized the millions of people imprisoned in NKVD Gulag camps into wartime production. He took control of the manufacture of armaments, and (with Georgy Malenkov) aircraft and aircraft engines. This was the beginning of Beria's alliance with Malenkov, which later became of central importance.

In 1944, as the Germans were driven from Soviet soil, Beria was in charge of dealing with the various ethnic minorities accused of anti-sovietism and/or collaboration with the invaders, including the Balkars, the Karachays, the Chechens, the Ingush, the Crimean Tatars, the Pontic Greeks and the Volga Germans. All these groups were deported to Soviet Central Asia (see "Population transfer in the Soviet Union.")

Abroad, Beria had met with Kim Il-sung, the Future leader of North Korea, several times when the Soviet troops had declared war on Japan and occupied the northern half of Korea from August 1945. Beria recommended that Stalin install a communist leader in the occupied territories.

One of the first such moves involved the Jewish Anti-Fascist Committee affair that commenced in October 1946 and eventually led to the murder of Solomon Mikhoels and the arrest of many other members. This affair damaged Beria; not only had he championed the creation of the committee in 1942, but his own entourage included a substantial number of Jews.

During the postwar years, Beria supervised installation of Communist regimes in the countries of Eastern Europe and hand-picked the Soviet-backed Leaders. Starting in 1948, Abakumov initiated several investigations against these Leaders, which culminated with the arrest in November 1951 of Rudolf Slánský, Bedřich Geminder, and others in Czechoslovakia. These men were frequently accused of Zionism, cosmopolitanism and providing weapons to Israel. Such charges deeply disturbed Beria, as he had directly ordered the sale of large amounts of Czech arms to Israel. Altogether, 14 Czechoslovak Communist Leaders, 11 of them Jewish, were tried, convicted, and executed (see Slánský trial). Similar investigations in Poland and other Soviet satellite countries occurred at the same time.

In other international issues, Beria (along with Mikoyan) correctly foresaw the victory (1949–1950) of Mao Zedong in the Chinese Civil War and greatly helped the Chinese communists' success by letting the Communist Party of China use Soviet-occupied Manchuria as a staging area and arranging large weapons-shipments to the People's Liberation Army, mainly from the recently captured equipment of the Japanese Kwantung Army.

Beria and all the other defendants were sentenced to death on 23 December 1953. When the death sentence was passed, Beria pleaded on his knees for mercy before collapsing to the floor and wailing and crying, but to no avail. The other six defendants were executed by firing squad on the same day the trial ended. Beria was executed separately. He was shot through the forehead by General Pavel Batitsky who had to stuff a rag into Beria's mouth to silence him. His final moments bore great similarity to those of his own predecessor, NKVD Chief Nikolai Yezhov, who begged for his life before his execution in 1940. His body was subsequently cremated and the remains buried in a forest near Moscow.

In the 1958 CBS production of "The Plot to Kill Stalin" for Playhouse 90, Beria was portrayed by E.G. Marshall.

Richard Condon's 1959 novel The Manchurian Candidate describes brainwashed Raymond Shaw, the "perfectly prefabricated Assassin," as "this dream by Lavrenti Beria."

In the 1964 science fiction novel by Arkady and Boris Strugatsky, Hard to Be a God, Beria is personified in the character Don Reba who serves as the king's minister of defence.

In the 1969 Doctor Who story The War Games, actor Philip Madoc based the coldly evil War Lord on Beria, even wearing his pince-nez spectacles.

Georgian film Director Tengiz Abuladze based the character of dictator Varlam Aravidze on Beria in his 1984 film Repentance. Although banned in the Soviet Union for its semi-allegorical critique of Stalinism, it premiered at the 1987 Cannes Film Festival, winning the FIPRESCI Prize, Grand Prize of the Jury, and the Prize of the Ecumenical Jury.

British actor Bob Hoskins played Beria in the 1991 film Inner Circle. He was portrayed by Roshan Seth in the 1992 film Stalin and, with an Irish accent, by David Suchet in Red Monarch.

Beria is a significant character in the opening chapters of the 1998 novel Archangel by British Novelist Robert Harris.

Prior to and during the war, Beria directed Sarkisov to keep a running list of the names and phone numbers of his sexual encounters. Eventually he ordered Sarkisov to destroy the list as a security risk, but the colonel retained a secret handwritten copy. When Beria's fall from power began, Sarkisov passed the list to Viktor Abakumov, the former wartime head of SMERSH and now chief of the MGB – the successor to the NKVD. Abakumov was already aggressively building a case against Beria. Stalin, who was also seeking to undermine Beria, was thrilled by the detailed records kept by Sarkisov, demanding: "Send me everything this asshole writes down!" Sarkisov reported that Beria's sexual appetite had led to him contracting syphilis during the war, for which he was secretly treated without the knowledge of Stalin or the Politburo (a fact Beria later admitted during his interrogation). Although the Russian government acknowledged Sarkisov's handwritten list of Beria's victims on 17 January 2003, the victims' names will not be released until 2028.

Beria appears in the third episode ("Superbomb") of the four-part 2007 BBC docudrama series Nuclear Secrets, played by Boris Isarov. In the 2008 BBC documentary series World War II: Behind Closed Doors, Beria was portrayed by Polish actor Krzysztof Dracz (pl).

Beria is a minor character in the 2009 Novel The Hundred-Year-Old Man Who Climbed Out the Window and Disappeared by Jonas Jonasson. Beria is described as the boss of the Soviet state's security and is in attendance at a meal with the main character and Stalin.

In 2012, his alleged personal diary from 1938 to 1953 was published in Russia.

He was also an important character in the 2013 Russian mini-series Kill Stalin, produced by Star Media.

Simon Russell Beale played Beria in the 2017 satirical film The Death of Stalin.