The board cut the benchmark rate by a quarter of a point to 2.25 percent, a shift from its hawkish policy stance that many analysts saw as caving in to government pressure to shore up growth.
However, one member, Moon Woo-sik, voted against, citing a steady recovery in the economy.
Moon, who was nominated by then central bank Governor Kim Choong-soo when he joined the board in April 2012, also said the central bank needed to prepare for problems that could arise if global interest rates increased after the end of US quantitative easing.
Another board member, who asked not to be named in the minutes, argued for a cut of 20 basis points rather than 25 but eventually voted to lower the policy rate to 2.25 percent from 2.50 percent.
Names are not usually given in the minutes but members who dissent from the majority can opt to reveal their identity.
The Bank of Korea next reviews policy on Sept. 12.