Prior to the 400  m final at the 2007 World Championships in Athletics in Osaka, Merritt stated his intent to beat all-comers. He achieved his first sub-44  second run, finishing in 43.96, and beat 2000 Olympic champion Angelo Taylor to the line. However, this was not enough to beat the reigning World and Olympic champion Jeremy Wariner, who was half a second ahead. Nevertheless, the silver medal was Merritt's first at a global championships over the 400  m. He again formed part of the United States' 4×400 meter relay team and, with fellow individual medallists Wariner and Taylor among the team, the American's eased to victory some three and a half seconds ahead of the Bahamians. With Wariner absent from the field, Merritt won the gold medal at the 2007 IAAF World Athletics Final.