The son of a fisherman, Suzuki attended the former Imperial Fisheries Institute and joined the Japan Fisheries Association. At the second postwar general election, in 1947, Suzuki won a seat in the lower house of the Diet (parliament) as a socialist. Two years later he switched to the conservative Liberal Party, forerunner of the Liberal-Democratic Party (Liberal-Democratic Party of Japan) (LDP), and he won reelection 12 times, during which period he held several cabinet posts. His abilities as a mediator brought him the chairmanship of the LDP's executive council a record 10 times, but he was virtually unknown abroad when elected prime minister on July 17, 1980. When his predecessor, Ōhira Masayoshi, unexpectedly died 10 days before an election, a three-week battle for succession resulted within the LDP. Suzuki, a loyal and longtime party worker, was the dark-horse winner of the LDP presidency, which assured him the prime ministership.

In office Suzuki upheld his political slogan, “politics of harmony,” while stressing moderate internationalism. In 1981 he attended a summit with U.S. President Ronald Reagan in which the two countries' relationship was defined as an “alliance.” The following year, however, Suzuki drew criticism for Japan's struggling economy and for his handling of the controversy that ensued after Japanese textbooks were revised to downplay the country's aggression against China during World War II. Suzuki lost support within the LDP, and in 1982 he decided not to seek reelection as the party's leader and thereby relinquished the post of prime minister. He retained his seat in the Diet, however, and continued to lead a sizable faction of the LDP. Suzuki remained active in politics until his retirement in 1990.