[11] Uncle Robert had been a taxi driver in Paris in the 1920s and had lost all his family in World War II.

In 1949, he played Ratmir Kholmov, a young master who had recently competed in the prestigious Chigorin Memorial in 1947, in a simultaneous exhibition.

[12][13] Alexander Koblents began tutoring him in 1949, after which Tal's game rapidly improved, and by 1951 he had qualified for the Latvian Championship.

Tal graduated in Literature from the University of Latvia, writing a thesis on the satirical works of Ilf and Petrov, and taught school in Riga for a time in his early twenties.

Tal made his first significant appearance at the 1956 USSR Chess Championship, sharing 5th–7th place with Lev Polugaevsky and Ratmir Kholmov.

[14] Grigory Levenfish called him "the most colourful figure of the championship" and a "great talent" who strove for "sharp and complicated play".

He won the 1958 Interzonal tournament at Portorož, Socialist Federal Republic of Yugoslavia, then helped the Soviet Union to win the 13th Chess Olympiad, being its fourth consecutive victory in Munich, West Germany.

Tal won with 20/28 points, ahead of Paul Keres with 18½, followed by Tigran Petrosian, Vasily Smyslov, Bobby Fischer, Svetozar Gligorić, Friðrik Ólafsson, and Pal Benko.

Tal's victory was attributed to his dominance over the lower half of the field;[18] whilst scoring only one win and three losses versus Keres, he won all four individual games against Fischer, and took 3½ points out of 4 from each of Gligorić, Olafsson, and Benko.

[20] In 1960, at the age of 23, Tal defeated the strategically-minded Mikhail Botvinnik in a World Championship match, held in Moscow, by 12½–8½ (six wins, two losses, and thirteen draws),[20] making him the youngest-ever World Champion (a record later broken by Garry Kasparov, who earned the title at 22, and broken again by Gukesh Dommaraju who earned the title at age 18).

[21] Tal's chronic kidney problems contributed to his defeat, and his doctors in Riga advised that he should postpone the match for health reasons.

Soon after losing the rematch with Botvinnik, Tal won the 1961 Bled supertournament in SFR Yugoslavia, by one point over Fischer, despite losing their individual game, scoring 14½ from nineteen games (+11−1=7) with the world-class players Petrosian, Keres, Gligorić, Efim Geller, and Miguel Najdorf among the other participants.

In 1962 at Curaçao, Netherlands Antilles, he had serious health problems, having undergone a major operation shortly before the tournament, and had to withdraw three-quarters of the way through, scoring just seven points (+3−10=8) from 21 games.

Exempt from the 1967 Interzonal in Sousse, Tunisia, he defeated Gligorić 5½-3½ in Belgrade in 1968, but then lost the semi-final match against Viktor Korchnoi in Moscow.

One of Tal's greatest achievements during his later career was an equal first place with Karpov (whom he seconded in a number of tournaments and world championships) in the 1979 Montreal (Canada) "Tournament of Stars", with an unbeaten score of (+6−0=12), the only undefeated player in the field, which also included Spassky, Portisch, Vlastimil Hort, Robert Hübner, Ljubomir Ljubojević, Lubomir Kavalek, Jan Timman and Larsen.

In 1988, at the age of 51, he won the second official World Blitz Championship (the first was won by Kasparov the previous year in Brussels, Belgium) at Saint John, Canada, ahead of such players as Kasparov, the reigning world champion, and ex-champion Anatoly Karpov.

[17] Tal played board nine for the USSR in the first match against the Rest of the World team at Belgrade, SFR Yugoslavia in 1970, scoring 2 out of 4.

He was on board seven for the USSR in the second match against the Rest of the World team at London, United Kingdom in 1984, scoring 2 out of 3.

His already fragile health suffered as a result, and he spent a great deal of time in the hospital, including an operation to remove a kidney in 1969.

His friend and fellow Soviet grandmaster Gennadi Sosonko reported that "effectively his entire organism had ceased to function.

He often sacrificed material in search of activity and initiative[20] which is defined as the ability to make threats to which the opponent must respond.

[28] Although Tal's sacrifices were formidable, his style of play was very risky, contributing to his negative record against world-class defensive players.

Although his playing style at first was scorned by ex-world champion Vasily Smyslov as nothing more than "tricks", Tal convincingly beat many notable grandmasters with his trademark aggression.

[30] Tal contributed little to opening theory, despite having a deep knowledge of most systems, the Sicilian and the Ruy Lopez in particular.