The reigning MLS Cup champions suffered a last-minute defeat at Seattle Sounders FC last week, and that disappointment was compounded on home soil Saturday as Hedges helped Dallas deny Sporting its first win of the season.
Kansas City thought it had done enough to win the match when Aurelien Collin headed home a corner kick from Benny Feilhaber in the 81st minute.
But the visitors answered with by converting a set piece of their own in stoppage time when Michel's delivery to the back post was turned in by Hedges.
The defender's strike, his first of the season, maintains FC Dallas' unbeaten start to life under new head coach Oscar Pareja as the club has taken four points from its first two matches.
Celebrity Breakups and divorces of 2014 [PHOTOS]