In 2004, Simpson became African Champion for a second time and followed this result with a ninth place at the 2004 Athens Olympics.

[3] Simpson reached the global podium for the first time at the 2005 World Championships in Athletics, taking third place with the second best performance of her career with a tally of 6375 points.

She missed the 2006 season but returned the year after with a gold medal performance at the 2007 All-Africa Games.

She was back to good form at the 2010 African Championships in Athletics, where she won a third heptathlon title in a score of 6031 points.

[3] She won the 2011 edition of the Multistars meeting in Desenzano del Garda with a score of 6270 points, defeating the 2010 champion Marina Goncharova.