Leonid Brezhnev became the First Secretary of the Soviet Communist Party of the USSR

Until about 1962, Khrushchev's position as Party leader was secure; but as the leader aged, he grew more erratic and his performance undermined the confidence of his fellow leaders. The Soviet Union's mounting economic problems also increased the pressure on Khrushchev's leadership. Outwardly, Brezhnev remained loyal to Khrushchev, but became involved in a 1963 plot to remove the leader from power, possibly playing a leading role. Also in 1963, Brezhnev succeeded Frol Kozlov, another Khrushchev protégé, as Secretary of the Central Committee, positioning him as Khrushchev's likely successor.

Khrushchev made him Second Secretary, literally deputy party leader, in 1964.

After returning from Scandinavia and Czechoslovakia in October 1964, Khrushchev, unaware of the plot, went on holiday in Pitsunda resort on the Black Sea. Upon his return, his Presidium officers congratulated him for his work in office. Anastas Mikoyan visited Khrushchev, hinting that he should not be too complacent about his present situation. Vladimir Semichastny, head of the KGB, was a crucial part of the conspiracy, as it was his duty to inform Khrushchev if anyone was plotting against his leadership. Nikolay Ignatov, who had been sacked by Khrushchev, discreetly requested the opinion of several Central Committee members. After some false starts, fellow conspirator Mikhail Suslov phoned Khrushchev on 12 October and requested that he return to Moscow to discuss the state of Soviet agriculture. Finally Khrushchev understood what was happening, and said to Mikoyan, "If it's me who is the question, I will not make a fight of it."[19] While a minority headed by Mikoyan wanted to remove Khrushchev from the office of First Secretary but retain him as the Chairman of the Council of Ministers, the majority, headed by Brezhnev, wanted to remove him from active politics altogether.

Brezhnev and Nikolai Podgorny appealed to the Central Committee, blaming Khrushchev for economic failures, and accusing him of voluntarism and immodest behavior. Influenced by the Brezhnev allies, Politburo members voted to remove Khrushchev from office. In addition, some members of the Central Committee wanted him to undergo punishment of some kind. But Brezhnev, who had already been assured the office of the General Secretary, saw little reason to punish his old mentor further. Brezhnev was appointed First Secretary, but at the time was believed to be a transition leader of sorts, who would only "keep the shop" until another leader was appointed.

Alexei Kosygin was appointed head of government, and Mikoyan was retained as head of state.

Brezhnev and his companions supported the general party line taken after Joseph Stalin's death, but felt that Khrushchev's reforms had removed much of the Soviet Union's stability. One reason for Khrushchev's ousting was that he continually overruled other party members, and was, according to the plotters, "in contempt of the party's collective ideals". Pravda, a newspaper in the Soviet Union, wrote of new enduring themes such as collective leadership, scientific planning, consultation with experts, organisational regularity and the ending of schemes. When Khrushchev left the public spotlight, there was no popular commotion, as most Soviet citizens, including the intelligentsia, anticipated a period of stabilisation, steady development of Soviet society and continuing economic growth in the years ahead.

As Brezhnev replaced Khrushchev as the new General Secretary of the Communist Party, he held ultimate political authority as the leader of the Soviet Union. However, he shared collective leadership with Nikolai Podgorny (the Chairman of the Supreme Soviet and nominal head of state) and Alexsei Kosygin, the Premier. Brezhnev soon would maximize his grip on power and would be the dominating authority in the collective leadership. Early policy reforms were seen as predictable.

In 1964, a plenum of the Central Committee forbade any single individual to hold the two most powerful posts of the country (the office of the General Secretary and the Premier).

Former Chairman of the State Committee for State Security (KGB) Alexander Shelepin disliked the new collective leadership and its reforms. He made a bid for the supreme leadership in 1965 by calling for restoration of "obedience and order". Shelepin failed to gather support in the Presidium and Brezhnev's position was fairly secure; he was able to remove Shelepin from office in 1967.

Khrushchev was removed mainly because of his disregard of many high-ranking organisations within the CPSU and the Soviet government. Throughout the Brezhnev era, the Soviet Union was controlled by a collective leadership (officially coined "Collectivity of leadership") at least through the late 1960s and 1970s. The consensus within the party was that the collective leadership prevailed over the supreme leadership of one individual. T.H. Rigby argued that by the end of the 1960s, a stable oligarchic system had emerged in the Soviet Union, with most power vested around Brezhnev, Kosygin and Podgorny. While the assessment was true at the time, it coincided with Brezhnev's strengthening of power by means of an apparent clash with Central Committee Secretariat Mikhail Suslov.

American Henry A. Kissinger, in the 1960s, mistakenly believed Kosygin to be the dominant leader of Soviet foreign policy in the Politburo. During this period, Brezhnev was gathering enough support to strengthen his position within Soviet politics. In the meantime, Kosygin was in charge of economic administration in his role as Chairman of the Council of Ministers. Kosygin's position was weakened when he proposed an economic reform in 1965, which was widely referred to as the "Kosygin reform" within the Communist Party. The reform led to a backlash, and party conservatives continued to oppose Kosygin after witnessing the results of reforms leading up to the Prague Spring. His opponents then flocked to Brezhnev, and they helped him in his task of strengthening his position within the Soviet system.

Brezhnev was adept at the politics within the Soviet power structure. He was a team player and never acted rashly or hastily; unlike Khrushchev, he did not make decisions without substantial consultation from his colleagues, and was always willing to hear their opinions.

During the early 1970s, Brezhnev consolidated his domestic position.

In 1977, he forced the retirement of Podgorny and became once again Chairman of the Presidium of the Supreme Soviet of the Soviet Union, making this position equivalent to that of an executive president. While Kosygin remained Premier until shortly before his death in 1980 (replaced by Nikolai Tikhonov as Premier), Brezhnev was the dominant driving force of the Soviet Union from the mid-1970s to his death in 1982