Answer
In the 2009-10 season, Millwall accomplished a notable feat under the astute leadership of manager Kenny Jackett and the invaluable contributions of players like Steve Morison. Together, they orchestrated Millwall's triumphant promotion to the esteemed English Football League Championship. This hard-fought triumph marked a pivotal moment in the club's history, propelling them to greater heights and further solidifying their position in the upper echelons of English football.