Alfred Kipketer has been competing in international 800-meter competitions since 2013. In July he took part in the U18 World Championships in Donetsk. He moved into the final, in which he won the gold medal in 1: 48.01 min. In 2014, he competed in May as part of the Kenyan 4 x 800 meter relay at the IAAF World Relays in the Bahamas. With a time of 7: 08.40 minutes, the quartet, with Kipketer as the final runner, won the gold medal. In June, Kipketer became the Kenyan junior champion over 8000 meters and a month later entered the U20 World Championships in Eugene. His time in the final of 1: 43.95 min, with which he won the gold medal, not only meant the world's best time for the juniors, but was also only 16 hundredths of a second behind the championship record set by Nijel Amos in 2012.
In 2015, the Kenyan relay around Kipketer was disqualified at the IAAF World Relays . With third place in the Kenyan Trials, he secured a place in the Kenyan team for the 800 meters and was able to start at the World Championships in Beijing. After confidently surviving the preliminary and semi-finals, he finished seventh in the final with a time of 1: 47.66 minutes. In the 2016 Olympic season, Kipketer ran a time of 1: 43.73 min in the national trials and thus secured the ticket for the Summer Olympic Games in Rio de Janeiro. During this time he was only slightly behind the season's best performance by his compatriot and world record holder David Rudisha . As in the previous year at the World Championships, Kipketer finished seventh in the final after a successful preliminary and semi-final run. A few weeks later he ran a personal best of 1: 42.87 minutes in Paris. In April 2017 he again took part in the IAAF World Relays . After winning the title with the 4 x 800 meter relay, this time the silver medal jumped out. Then he missed the qualification for the World Championships in London against the national competition. In 2018 he missed qualifying for the Commonwealth Games in the Australian Gold Coast. Throughout the season, he attended a large number of athletics meetings in Europe. In 2019 he was also unable to qualify for the World Championships.
In January 2020, Kipketer was suspended from the Athletics Integrity Unit after failing to take three tests for a doping control. The suspension will initially last until Kipketer comments on the allegations.