Leshoure finished with 70 yards on 16 carries while quarterback Matthew Stafford went 22-for-33 through the air for 285 yards as the Lions (4-4) clawed their way back to .500 with a second straight win.
Detroit also turned in a stellar defensive performance, limiting Jacksonville to just one first down in the first half with a sack and two interceptions.
Calvin Johnson led Detroit's receivers with seven catches for 129 yards.
The Jaguars (1-7), meanwhile, continued to tailspin, dropping their fifth consecutive game.
Blaine Gabbert managed 220 yards on 27-for-38 efficiency with two touchdowns and two interceptions for Jacksonville.