BOSTON — When Jeff Bauman woke up in a hospital bed on Tuesday, an air tube was down his throat, both of his legs had been amputated at the knee, and his father was by his side. He tried to talk, but he could not.

He looked angry, as he motioned his arms up and out like shock waves and mouthed: “Boom! Boom!”

Jeff Bauman is the man in the photograph that has become an icon of the Boston Marathon attack, the one showing a bloodied, distraught young man, holding his left thigh, being wheeled away by a man in a cowboy hat. If the world could not identify him immediately, Mr. Bauman’s father — also named Jeff Bauman — certainly could.

That was his son with his legs destroyed, wearing a favorite shirt. That was his son.

When the explosions went off at the Boston Marathon, Jeff Bauman, 52, called his son’s cellphone again and again — no answer. He knew his son was there, to cheer for his girlfriend, Erin Hurley, who was running her first Boston Marathon. For an hour, he kept calling, calling. No answer.