Matt Ruben, president of the Northern Liberties Neighbors Association, the group that led the opposition to the project, praised the decision.
"I think it takes courage for the mayor to veto the Spring Garden bill," Ruben said. "The community certainly appreciates the mayor adding his voice to ours."
Michael Driscoll, a partner in Finnigan's who wanted to add the balconies to expand his catering business, could not be reached for comment.
The balconies would have been supported by columns and would have projected 14 feet over the sidewalk. Finnigan's also hoped to build a vestibule on the first floor that would occupy about 10 feet of the length of the sidewalk, the mayor's Tuesday letter to Council said.
Nutter said he would allow related legislation to become law. That bill permits Finnigan's to close Bodine Street to traffic and use it for an outdoor plaza with dining.
Both bills had passed unanimously - as do most zoning issues supported by the Council member representing the district - but a Council override of the veto is not a certainty.
The sponsor of the two bills, First District Councilman Mark Squilla, said Tuesday he wasn't sure he would ask for an override because he didn't know how that would affect talks between Finnigan's and the neighbors.
Squilla had supported the bills but urged Finnigan's to reach some accommodation with the community.
Squilla said he wanted to talk to the rest of Council before making a decision, but he expressed general disappointment with Nutter's veto.
Former Democratic State Sen. William G. Stinson opened the bar in the old Standard Casket Co. building in 1997 with Driscoll and lawyer Charles Volz Jr.
One early investor was U.S. Rep. Bob Brady, the city's Democratic Party chief, but he has said he gave up his interest in 1998. Finnigan's remains a popular site for political events.
Contact staff writer Miriam Hill at 215-854-5520, email@example.com or @miriamhill on Twitter.