The only difference these days is that now Christerson, an unassuming man who shuns the limelight and the camera lights, is a walking medical marvel, reports CBS News Correspondent Elizabeth Kaledin.
The red bag he carries is not his lunch; it's the batteries that power his completely self-contained artificial heart.
Christerson had the heart implanted on Sept. 13, 2001. Of seven men who participated in the experiment, he is the only one who has lived long enough to leave the hospital and go home.
Before the operation, Christerson had just days to live. When the terrorist attacks of Sept. 11 delayed his surgery, doctors Laman Gray and Rob Dowling didn't think he'd make it.
"He was so sick the concern was, 'Could he survive another day or is he going to be in a sense, another victim of the terrorist attacks?'" said Dowling, a heart surgeon at Jewish Hospital.
Doctors Gray and Dowling removed Christerson's badly damaged heart and replaced it with a device known as the abiocor -- a plastic and metal heart about the size of a grapefruit.
The artificial heart works much like a natural heart, by pumping blood to the lungs and to the rest of the body. No wires or tubes pass through the skin; instead, power is transmitted across the skin.
The abiocor heart has been controversial though: some ethicists argued human subjects were just part of a risky science experiment and would never achieve a reasonable quality of life after the surgery.
But Christerson has proved them wrong. After a long recuperation -- and constant physical therapy -- the new heart has allowed him to attend a NASCAR race, celebrate his 55th wedding anniversary and witness the birth of his first great grandchild.
Is it an experiment? Absolutely, doctors admit -- but one that might some day help thousands of people.
"If we can add five years to someone's life and add it so that they have a quality of life, I think that's extremely important and that's certainly what our goal is," said Gray.
For Tom Christerson, that goal has been met.