Frenchman Kevin Mayer led throughout the day to win the world decathlon title on Saturday and fill the void left by Ashton Eaton's retirement - although he almost threw it all away on the pole vault.
Freimuth, bronze medalist at the Beijing World Championships two years ago, threw 51.17 meters, the longest of the competition, to leave him on 6,272 points with Olympic silver medalist Mayer on 6,296.
France's Mayer took home the gold, with teammates Freimuth and Kazmirek winning silver and bronze respectively.
"I just wanted to say you are the most unbelievable public in the world and I thank you for that", he said in an address to the sell-out 60,000-seater London Stadium.
Mayer, the overnight leader, recorded the third fastest time of 13.75 seconds in the 110 meters hurdles but could manage only seventh place with a throw of 47.14 in the discus.
In the last event of the morning session, Warner cleared a season-best 4.70 metres in pole vault, but missed all three of his attempts at 4.80 to finish fourth in his group. Warner was in a medal position after posting the best time among all athletes in the 110m hurdles but faded over the final four events on day two of decathlon action.
First, the USA's former two-time world champion Trey Hardee went down hard before Russian Ilya Shkurenyev, competing as a neutral, pulled up clutching his hamstring after the penultimate flight of barriers.