He joined the National Defense Forces, a precursor to the Republic of Korea Army, shortly after his graduation from the Kenkoku University towards the end of World War II.

He served as a division commander during the Korean War[1] and a military attaché in the Embassy of South Korea, Washington, D.C. in 1952[2] before becoming director of the Joint Chiefs of Staff at the Ministry of National Defense in 1954.

[7] During his tenure, political violence continued at universities throughout South Korea as groups labeled by the regime as "leftist radicals" advocated for the overthrow of the Government.

[10] After months of negotiations, Kang took part in historic talks with his North Korean counterpart, Prime Minister Yon Hyong-muk.

[11][12][13] The highest-level contact between the two Governments since 1945, the exchange of visits by respective prime ministers were aimed at reducing tension on the peninsula and an eventual reunification.

[14] The first meeting occurred on 5–6 September 1990 in Seoul, permitting both sides to directly address their concerns on issues regarding disarmament, United States troop withdrawal, the release of political prisoners, visitation rights, and reunification; the tone remained amiable.

[18] Even with the dismissive position of North Korean officials, soccer matches and folk-music-concert exchanges did take place in the subsequent months.

[18][19] The third meeting in December failed to come to a compromise over a proposed "declaration of non-aggression,"[20] which had been on the table since September; however both sides agreed yet again to continue talks the following February.