Harting's fourth attempt in the discus was measured at 69.11 meters (226.74 feet), nearly a full meter better than silver medalist Piotr Malachowski of Poland, who threw 68.36. Estonia's Gerd Kanter was third at 65.19.
The only other man to win the discus at more than two world championships is Lars Riedel, Harting's German countryman. Riedel won the event four times from 1991-97 and again in 2001.
Harting's 2009 world championship also saw Malachowski win silver and Kanter take the bronze. In 2011, Kanter was the runner-up.
Isinbayeva is the first woman to win the pole vault world title three times. She also took gold in 2005 and '07. She was the only vaulter to clear 4.89 meters (16.04 feet) Tuesday while Jennifer Suhr, who won the 2012 Olympics gold for the United States, was second at 4.82 and Cuba's Yarisley Silva was third, also at 4.82.
Ganna Melnichenko of Ukraine totaled 6,586 points to win the heptathlon. She stayed just close enough to Canada's Brianne Theisen Eaton in the 800 to protect the points lead she'd built. Theisen Eaton, whose husband Aston Eaton won the decathlon Sunday, totaled 6,503 points for silver. The Netherland's Dafne Schipper was third with 6,477 points.
U.S. runner LaShawn Merritt claimed his second world championship in the 400, turning a time of 43.74 seconds, which is the fastest time in the event this year. Tony McQuay, also of the United States, was second in 44.40 and Luguelin Santos of the Dominican Republic took the bronze medal with a time of 44.52.
The 800 went to Mohammed Aman of Ethiopia with U.S. runner Nick Symmonds second. Aman was clocked at 1 minute, 43.31 seconds with Symmonds coming in at 1:43.55. Djibouti's Luguelin Santos was third in 1:43.76.
Milcah Chemos Cheywa of Kenya turned in a time of 9 minutes, 11.65 seconds in the 3,000-meter steeplechase. It was her first world championships after finishing third in 2009 and '11. Lidya Chepkurui, another Kenyan, took the silver medal in 9:12.55 and Sofia Assefa, the first of three consecutive Ethopian finishers, claimed the bronze medal in 9:12.84.
Russia went 1-2 in the women's 20-kilometer walk. Elena Lashmanova added the world championship to her 2012 Olympic gold, covering 20 km in 1 hour, 27 minutes, 8 seconds. Anisya Kirdyapkina was second, 3 seconds after Lashmanova and China's Liu Hong, a minute after that, took third.
Merritt's gold medal was the fourth for the United States in the championships, which leads the charts. The Americans have the most overall medals with five silver and a bronze for a total of 10. Russia, with three gold, a silver and two bronze medal is second with six medals. Ethiopia, Germany and Kenya have all won two gold medals and five medals overall.