He's 55, a soft-spoken black belt in karate with a degree in early-childhood education. His hands are large enough to catch a knuckleballer.
About an hour later, we met in Wyndmoor, where he grew up, as he was heading through the horizontal rain to Barbara Shoemaker's center-hall Colonial on Willow Grove Avenue. Gallagher had a deal for me: If I wanted to shadow him for a morning, I'd have to hold his ladder.
Irene was already a New Yorker when we got to Shoemaker's house, but winds still gusted to 40 m.p.h. as Gallagher eased his fiberglass long ladder off his right shoulder and set it against a second-floor gutter.
"Just make sure I don't go flying off the roof," he said about 28 feet off the ground. "I don't want this to be an obit. But if it's an obit, make it one of those nice obits."
Shoemaker is retired, a former paralegal for a Center City firm. Her husband was in Washington when Irene arrived. She was afraid to look in her basement.
Even when a tornado warning interrupted her viewing of The Razor's Edge on TV Saturday night, she refused to consider the cellar. She figured she'd need a canoe.
Lesser storms than Irene had breached her basement this summer. From his Chevy truck, Gallagher could see what was wrong: gutters stuffed with leaves and nuts and silt and flowers from another season.
Sure enough, all four wire strainers he checked were clogged, blocking water from flowing through the downspouts. Around the back of the house, he found another problem. Someone had flattened the leader at the tip of the spout. "Landscaper," Gallagher suspected. With a pair of snips, he freed a gusher of brown muck.
Gallagher has been a roofer for 31 years. He grew up in Germantown, went to school in Springfield, finished Temple, taught for a year, joined his older brother as a roofer.
He was 25 when he took his first bad fall - a cartoon tumble, he said. A coworker grabbed Gallagher's leg, making him smack his face onto the roof and then bounce off a railing and splat onto concrete steps. He cataloged the breaks of his trade: "fingers, wrist, collarbone, ribs."
Since Thursday, Gallagher has been running on fumes, replacing shingles, plugging leaks, cleaning gutters. The hours have required repeated trips to Wawa for V8 juice, which his sensei recommends - the same sensei who called early Sunday and guessed that Gallagher would be crazy enough to be out on the streets.
Gallagher spent the morning crisscrossing eastern Montgomery and Bucks Counties, avoiding swollen creeks and downed limbs, skirting roadblocks, checking on customers, and meeting with coworker Frank Cybularz, who had his own punch list of properties. We parted company as Gallagher was heading to a house in Schwenksville.
"All in all, it could have been a lot worse," he said. "I figured with strong winds, a lot more shingles would have blown off, and once that happens, they fall like dominoes, and that can mean a lot of damage. But that's not the case."
He figured he'd work for about six hours, go home, then wait for more calls. He wasn't going to make as much money as he expected, but the good news was that most of his past work for his customers had held up fine.
"I may not make great money today," he said, "but I'll make great fans."
Contact columnist Daniel Rubin at 215-854-5917, firstname.lastname@example.org,
or @danielrubin on Twitter. Read his blog at philly.com/blinq.