The Bombers broke through 50,000 members for the first time in 2011, and pushed their membership target to 60,000 this year.
With just over two weeks before the Bombers' season starts, the club has fewer than 42,000 members. Hird said the falling total would hold back success at the club.
"Last year we achieved 50,000 members. We had a fantastic year of building, developing and getting our players better," Hird told Bomber TV.
"Currently, we are sitting well below our target. We cannot be successful, we cannot be a premiership team, without your help."
Essendon supporters have also been slow to donate to the club's 'Flight Plan' to support the move from its Windy Hill base to Melbourne Airport.
"The players, the coaches and the administration of the Essendon Football Club is working very hard so that we can become the best club we can and ultimately win premierships very soon," Hird said.
"You guys, as supporters, give us the support and by buying a membership allow us to be as good as we can be."
Follow Callum Twomey on Twitter at @AFL_CalTwomey.
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