Born in Riwon County, South Hamgyong Province in July Juche 27 (1938), she began her career at the Amnokgang Sports Team in 1958.

Out of desire to add luster to the honor of the country with gold medals, Sin devoted her all to training. She ran scores of kilometers every morning, overfulfilling the daily training assignments given by coaches.

Not long after, she placed first in the domestic women's track-and-field.

She set the world record in the 800-meter race with two minutes and 4.5 seconds at an international track and field tournament held in the former Soviet Union in July 1960, renewing the tournament record which had been fixed for 15 years. At that time, she came in the limelight of the Soviet media.

She also broke the 400-meter race world record at the international track and field tournament, with the DPRK, China and Mongolia in attendance, in October 1960 and set world records in 400-meter and 800-meter races at international tournaments in 1962 and 1963.

She bettered the 400-meter and 800-meter race world records, each with 51.4 seconds and one minute and 59.1 seconds at the 1st GANEFO (Games of New Emerging Forces) held in 1963.

As an undisputable "queen" in the world's track and field, Sin Kum Dan set 11 world records, bringing to her country 28 gold medals. Later, as a coach, she had trained a number of race aces before her retirement.

Sin is a winner of Kim Il Sung Prize and the title of the People's Athlete.