Dr. McAllister was born and raised in Andover, Massachusetts. The fourth of five sons, Dr. McAllister was educated at Philip's Academy Andover, Colby College and Tufts School of Medicine. After graduating from medical school in 2000, Dr. McAllister fulfilled a six-year commitment to the US Air Force stationed first at Wright-Patterson Air Force Base in Dayton, Ohio and then Kirtland Air Force Base in Albuquerque, New Mexico. When Major McAllister's military commitment ended in June 2006, he decided to return to his home-state of Massachusetts to start Performance Pediatrics.

Dr. McAllister is a board-certified pediatrician and a Fellow of the American Academy of Pediatrics (FAAP). He is credentialed with Jordan Hospital in Plymouth and Children's Hospital Boston. Dr. McAllister has been appointed as the Silver Lake Regional School District's School Physician for the 2008-2009 school year.