The ABC comedy has received 14 nominations for this year's awards, having won eight Emmys since 2010.
"I think we do worry that people won't root for us as much as they did before we won," Levitan told Deadline, adding: "We're still very much invested in winning and whatever comes with that - winning and what it represents."
The exec producer explained that being nominated for a third year running is a "very strange and new experience".
"You don't want people to think we don't care and [that] we're past that," he said. "But at the same time, you don't want to seem presumptuous.
"This is a very strange and new experience for me - to be in this position where we have won two Emmys in a row and are going for a third. We have to be even better because there will be a lot of people looking to say, 'Where else can I cast my vote?'"
The stars of Modern Family recently sued producers 20th Century Fox Television following unsuccessful contract negotiations, but later struck a new salary deal.
Each member of the show's adult cast is now expected to be paid around $170,000 (£108,000) to $175,000 (£111,000) per episode.
The 2012 Primetime Emmy Awards will air on September 23 on ABC.
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