That change, along with another that removed a layer of decorative cladding, had created some doubt about how the council might rule.
If they were to stand side by side, the Willis Tower would probably appear to be the larger building to most bystanders. In fact, someone standing in the Willis Tower's observation deck would have to look down to see One World Trade Center's roof.
This marks the second time that the Willis Tower has lost a "tallest" title in a disputed decision.
Back in 1996, the Council on Tall Buildings and Urban Habitat sparked controversy when it declared the Petronas Twin Towers in Malaysia taller than the Willis. That decision, like the one involving One World Trade Center, also rested on whether to count slender, decorative spires in the total height measurement.
Chicago Mayor Rahm Emanuel seemed nonplussed with Tuesday's decision.
"I would just say to all the experts gathered in one room: If it looks like an antenna, acts like an antenna, then guess what? It is an antenna," he told reporters.
Bella Engstrom, a tourist from Sweden visiting the World Trade Center site, said she thought any measurement of the building should stop at the highest point a person can stand in the tower.
"I think it's as high as you can go. You stop there," she said.
Kevin Corrigan, a union carpenter working at the Trade Center site Tuesday dismissed the height debate as an issue for academics, not workers on the job.
"Getting it built. That's what we care about," he said.
In a joint statement, the Port Authority, its marketing partner, the Durst Organization, and Childs' architectural firm, Skidmore, Owings & Merrill, said the building's creators had "long celebrated the height of 1,776 feet as an unwavering principal" of its design.
"This iconic building represents the resilience of America and today's decision recognizes One World Trade Center's rightful place in history," they said.
The new World Trade Center tower remains under construction and is expected to open next year.
When it does, it will be the world's third-largest skyscraper, behind the 2,717-foot Burj Khalifa in Dubai and the 1,972-foot Makkah Royal Clock Tower Hotel in Mecca, Saudi Arabia. Even that distinction may not last: Six even taller towers are under construction in Asia.
- Watch live at the Democratic National Convention
- Germany: Syrian asylum seekers blows himself...
- Verizon buys Yahoo for $4.83B, marking end of...
- Gunfire at teen nightclub party leaves 2...
- Trump taunts claims that Russia hacked DNC...
- Dems' division, emails roil party on Day 1 of...
- Athletes using sports platforms to push for...
- Germany: IS claims responsibility for attack...
- If Mitt Romney endorsed Gary Johnson,... 69
- Hillary Clinton promises steady hand in... 56
- Sarah Silverman: Bernie-or-bust Dems... 49
- Is Bernie Sanders an atheist? 44
- Trump says Russia should find Clinton's... 43
- Obama boosts Clinton: Carry her like... 41
- Clinton wins historic nomination,... 37
- After turmoil, Sanders, Michelle Obama,... 31