The 1998 season proved to be a breakthrough for Johnson. She set a lifetime best of 12.88 seconds in the 100 m hurdles and also dipped under 55 seconds for the 400 m hurdles for the first time. Her international senior debut followed at the 1998 Goodwill Games, where she narrowly missed out on a medal in fourth place behind Batten. (She had also been fourth at the 1997 Summer Universiade as a collegiate athlete).