On June 7, Katie McKennon was on her first day as a lifeguard at the Southampton subdivision pool.

It didn’t take long for her mettle to be tested as the only lifeguard on duty. And she passed with flying colors, with an assist from another pool patron.

Her eyes on the lone swimmer, McKennon leapt into the pool after he stopped moving while underwater. She found the 16-year-old boy unconscious, so she pulled him out using a technique that adapts her body to serve as a sort of “rescue board.”

McKennon then shouted for someone to call 911 and a nurse came forward to help.

“I noticed he had a really faint pulse and was not breathing,” McKennon said.

Rescue breathing was administered and the victim coughed up water; it was later determined that he had a seizure while underwater, McKennon said.

The nurse, who works with infants at Northside Hospital, took over the resuscitation immediately with McKennon assisting, she said.

Paramedics ultimately took the victim to the hospital. Several days later he came back to the pool to meet with McKennon, “so he could get his story straight,” she said.

Having graduated from Sandy Creek High School, McKennon may well be the first of the Class of 2011 to have actually saved a life. She was in the position to do so in part because of her ambition to one day become a Navy fighter pilot.

McKennon said the job would help set her up well for that Navy career, as she now has certifications not just as a lifeguard but also in first aid, cardiopulmonary resuscitation and using an automatic external defibrillator.

As for coming through in the clutch in a life-threatening moment?

“I felt like it was a sign,” McKennon said, noting that she enjoys lifeguarding and appreciates the responsibility assigned to her.