Early on in his tenure, Kosygin challenged Brezhnev's right as general secretary to represent the country abroad, a function Kosygin believed should fall into the hands of the head of government, as was common in non-communist countries.
This was actually implemented for a short period, which led Henry A. Kissinger to believe that Kosygin was the leader of the Soviet Union.
Kosygin, who had been the chief negotiator with the First World during the 1960s, was hardly to be seen outside the Second World after Brezhnev consolidated his position within the Politburo, but also due to Andrei Gromyko's dislike of Kosygin meddling into his own ministerial affairs.

The Six-Day War in the Middle East had the effect of increasing Soviet–American cooperation; to improve relations even further, the United States Government invited Kosygin to a summit with Lyndon B. Johnson, the President of the United States, following his speech to the United Nations.
At the summit, which became known as the Glassboro Summit Conference, Johnson and Kosygin failed to reach agreement on limiting anti-ballistic missile systems, but the summit's friendly and even open atmosphere was referred to as the "Spirit of Glassboro".
Relations between the two countries improved further when the 1970 Moscow Treaty was signed on 12 August 1970 by Kosygin and Gromyko and Willy Brandt and Walter Scheel who represented West Germany.
In 1971 Kosygin gave an extensive interview to the American delegation that included David Rockfeller presenting his views on the US-Soviet relations, environment protection, arms control and other issues.

 
Kosygn developed close friendly relationship with the President of Finland Urkho Kekkonen, that helped USSR to maintain active mutual trade with Finland and to keep it away from Cold War confrontation.

In 1972, Kosygin signed a Treaty of Friendship and Cooperation with the government of Iraq, building on strong Soviet ties to the Iraqi Arab Socialist Ba'ath Party and previous close relations with Iraqi leader Abd al-Karim Qasim.

Kosygin protected János Kádár's economic reforms and his position as leader of the People's Republic of Hungary from intervention by the Soviet leadership.
Polish leader Władysław Gomułka, who was removed from all of his posts in 1970, was succeeded by Edward Gierek who tried to revitalise the economy of the People's Republic of Poland by borrowing money from the First World.
The Soviet leadership approved both countries' respective economic experiments, since it was trying to reduce its large Eastern Bloc subsidy programme in the form of cheap oil and gas exports.
During the discussions within the Soviet leadership of a possible Soviet invasion of Czechoslovakia Kosygin reminded leaders of the consequences of the Soviet suppression of the 1956 Hungarian revolution.
Kosygin's stance became more aggressive later on when he understood that the reforms in Czechoslovakia could be turned against his 1965 Soviet economic reform.

We should tell Taraki and Amin to change their tactics.
They still continue to execute those people who disagree with them.
They are killing nearly all of the Parcham leaders, not only the highest rank, but of the middle rank, too.

— Kosygin speaking at a Politburo session.

Kosygin acted as a mediator between India and Pakistan in 1966, and got both nations to sign the Tashkent Declaration.
Kosygin became the chief spokesman on the issue of arms control.
In retrospect, many of Kosygin's co-workers felt he carried out his work "stoically", but lacked "enthusiasm", and therefore never developed a real taste for international politics.

The Sino–Soviet split chagrined Kosygin a great deal, and for a while he refused to accept its irrevocability; he briefly visited Beijing in 1969 due to increased tension between the USSR and China.
Kosygin said, in a close-knit circle, that "We are communists and they are communists.
It is hard to believe we will not be able to reach an agreement if we met face to face".
His view on China changed however, and according to Harold Wilson, former Prime Minister of
Early on in his tenure, Kosygin challenged Brezhnev's right as general secretary to represent the country abroad, a function Kosygin believed should fall into the hands of the head of government, as was common in non-communist countries. This was actually implemented for a short period, which led Henry A. Kissinger to believe that Kosygin was the leader of the Soviet Union. Kosygin, who had been the chief negotiator with the First World during the 1960s, was hardly to be seen outside the Second World after Brezhnev consolidated his position within the Politburo, but also due to Andrei Gromyko's dislike of Kosygin meddling into his own ministerial affairs.
The Six-Day War in the Middle East had the effect of increasing Soviet–American cooperation; to improve relations even further, the United States Government invited Kosygin to a summit with Lyndon B. Johnson, the President of the United States, following his speech to the United Nations. At the summit, which became known as the Glassboro Summit Conference, Johnson and Kosygin failed to reach agreement on limiting anti-ballistic missile systems, but the summit's friendly and even open atmosphere was referred to as the "Spirit of Glassboro". Relations between the two countries improved further when the 1970 Moscow Treaty was signed on 12 August 1970 by Kosygin and Gromyko and Willy Brandt and Walter Scheel who represented West Germany. In 1971 Kosygin gave an extensive interview to the American delegation that included David Rockfeller presenting his views on the US-Soviet relations, environment protection, arms control and other issues. 
 
Kosygn developed close friendly relationship with the President of Finland Urkho Kekkonen, that helped USSR to maintain active mutual trade with Finland and to keep it away from Cold War confrontation. 
In 1972, Kosygin signed a Treaty of Friendship and Cooperation with the government of Iraq, building on strong Soviet ties to the Iraqi Arab Socialist Ba'ath Party and previous close relations with Iraqi leader Abd al-Karim Qasim.
Kosygin protected János Kádár's economic reforms and his position as leader of the People's Republic of Hungary from intervention by the Soviet leadership. Polish leader Władysław Gomułka, who was removed from all of his posts in 1970, was succeeded by Edward Gierek who tried to revitalise the economy of the People's Republic of Poland by borrowing money from the First World. The Soviet leadership approved both countries' respective economic experiments, since it was trying to reduce its large Eastern Bloc subsidy programme in the form of cheap oil and gas exports. During the discussions within the Soviet leadership of a possible Soviet invasion of Czechoslovakia Kosygin reminded leaders of the consequences of the Soviet suppression of the 1956 Hungarian revolution. Kosygin's stance became more aggressive later on when he understood that the reforms in Czechoslovakia could be turned against his 1965 Soviet economic reform.
We should tell Taraki and Amin to change their tactics. They still continue to execute those people who disagree with them. They are killing nearly all of the Parcham leaders, not only the highest rank, but of the middle rank, too.
— Kosygin speaking at a Politburo session.
Kosygin acted as a mediator between India and Pakistan in 1966, and got both nations to sign the Tashkent Declaration. Kosygin became the chief spokesman on the issue of arms control. In retrospect, many of Kosygin's co-workers felt he carried out his work "stoically", but lacked "enthusiasm", and therefore never developed a real taste for international politics.
The Sino–Soviet split chagrined Kosygin a great deal, and for a while he refused to accept its irrevocability; he briefly visited Beijing in 1969 due to increased tension between the USSR and China. Kosygin said, in a close-knit circle, that "We are communists and they are communists. It is hard to believe we will not be able to reach an agreement if we met face to face". His view on China changed however, and according to Harold Wilson, former Prime Minister of 
Alexei Kosygin