Ibrahim Shah was working the grill at his uncle's food truck across from City Hall on Friday, grilling up breakfast sandwiches for a busy crowd.

The day before, on a large building just around the corner, a world-famous artist had begun work on a giant mural - a mural of Ibrahim.

But by Friday morning, Ibrahim had yet to see the mural - had yet to see his face so high in the sky.

"I have been too busy here with my job," he said, cracking eggs on the grill.

He would go when he could get a break.

The story of how Ibrahim - who immigrated to Philadelphia from the Swat Valley in Pakistan 14 months ago - came to be on the side of a building in Center City began one day last month when the French artist known as JR came to town.

The social-minded street artist, renowned for pasting towering portraits on city surfaces across the globe, JR was looking for a new face. A face of those so often overlooked. A face of an immigrant.

He strolled blocks near City Hall. Then, he came upon the food truck where Ibrahim works with his cousin Farman Khan.

Struck by Ibrahim's bright blue eyes and his smile and energy, JR asked if he could take Ibrahim's photograph. He told him it was for a mural. A big one.

Ibrahim asked Farman to man the grill. When the camera clicked, he struck a serious expression.

JR went on his way. Ibrahim went back to the grill.

On Thursday, JR stepped out onto metal scaffolding hanging from the side of the Graham Building near Dilworth Park. With reporters and photographers watching from a nearby rooftop, the street artist used a brush to paste a massive print of Ibrahim's photo across the building. When it is completed this weekend, it will stretch 15 stories.

Titled Migrants, Ibrahim, Mingora - Philadelphia, the mural is an installment of the Mural Arts Program's "Open Source" project, a series of temporary outdoor art installations that aim to call attention to social issues.

Ibrahim's photo is an exploration of immigration. Partially obscured by another building, the mural purposefully lends the impression that Ibrahim is climbing out from the shadows. A metaphor for all the Ibrahims scratching out a living every day.

In Ibrahim's face, JR said he saw the perfect subject.

"His eyes and expression tell everything," the artist said.

Ibrahim grew up in a family of six in a village surrounded by mountains - and later besieged by fighting. When he was a child, his father came to Philadelphia to work on a food truck with an uncle. But he grew sick and died.

Ibrahim went to college in Pakistan. He studied sociology. But there was "no work, no nothing," he told me Friday. And the Swat Valley was boiling with fighting between the Pakistani army and the Taliban. His uncle offered him a job in the food truck, and he said yes and packed his bags.

He misses what he left behind.

He mother and sister. His fiancee. His friends who drove into the mountains with him on weekends so they could all play music and dance - his friends who gave him a silver braided ring with purple stone as a going-away gift.

His 1990 white Toyota Corolla that he washed by hand.

But he loves his new home.

"I am happy here," he said, smiling.

The food truck, Khan Food Express, sits at 15th and Market, the small back window framing City Hall. The truck is narrow and hot. He works 11-hour days. His body aches. But he has learned to work fast on the grill.

"Thank you. Have a nice day, OK," he tells the customers.

He lives with Farman and his aunt and uncle in a house on Ritner Street. He likes South Street and American pizza and the Shampoo Nightclub, which he and his cousins recently visited.

In his long days in the truck, he daydreams of starring in action movies like his favorite Bollywood actors. When he thinks of his future, he has hopes of one day owning his own food truck or a cab.

"I want to make money," he said.

We walked to see the mural. At 16th and Chestnut Streets, he craned his neck and looked up, the crowds bustling past, not seeming to notice the man who was looking at the towering image of himself.

"Wow," he said. "It's nice."

He would send photos home to his mother and fiancee, he said. They will think he's famous, he said.

Then his phone rang. It was time to go. He was needed at the food truck.