Johnston hit .292 with 106 hits in 363 at bats for the Lake Elsinore Storm. In 95 games he had 19 doubles, four triples, eight homers, 56 runs scored and 51 RBIs. He drew 36 walks compared to 82 strikeouts.

Johnston hit .184 with four doubles, three runs scored and seven RBIs over 12 Storm playoff games.

2006

Seth Johnston went 1-for-10 with a run scored and four K's in a three-game rehab assignment with the AZL Padres.

Johnston hit .275 with 126 hits in 458 at bats for the Fort Wayne Wizards. In 112 games he collected 33 doubles, ten homers, 58 RBI's and 72 runs scored. He also drew 32 walks while whiffing 80 times.

2005

In 47 games for the Ems, Seth Johnston hit .253 with eight doubles, one triple and two homers. He knocked in 23, including seven in one game, and scored 15.

Johnston was taken in the fifth round of the 2005 Draft by the Padres. Johnston had a successful career at Texas, going to the College World Series all four years.