ISTANBUL — In a prominent spot on a shelf close to his desk, Fuat Tosyali keeps a reminder of what his life was like long before he became a steel magnate and one of the richest people in Turkey, with a penthouse office outside Istanbul and a Mercedes limousine parked out front.

It is a black and white photograph of a young man polishing a stovepipe.

The young man is Mr. Tosyali, and in many ways the photograph tells the story of how far the Turkish economy has come. Mr. Tosyali’s road from poverty to wealth mirrors Turkey’s journey from tattered former empire to Mediterranean powerhouse with growth rates to rival China, at least until the economy took a steep dive last summer.

In an interview in his office, which is furnished with ample couches covered in beige leather and a polished black coffee table the size of a double bed, Mr. Tosyali professed confidence despite a downturn that has been exacerbated by the punitive tariffs imposed on Turkish steel by the United States.

“This is my 51st year in the business,” said Mr. Tosyali, 55, who began helping out his father’s metalworking shop before he was old enough to go to school. “I have seen many crises.”