Mackie’s celebrity clientele has included: Broadway actress Jennifer Holiday, along with actors Wendell Pierce and John Goodman – transforming 63-year old Terminator 1&2 star Linda Hamilton’s body and performance to a level not seen before in Hollywood for her role of Sarah Connor in the 2019 Terminator Dark Fate movie, at the request of Hollywood creator, producer, and director James Cameron.

While countless professionals – athletes, actors, law enforcement, and special forces – have received career-extending help from the health and fitness guru, Mackie has also transformed the lives of hundreds of non-athletes struggling with health and weight problems, poor nutrition, and a lack of motivation in his hospital-affiliated wellness programs.

Over his 43 year career, Mackie has designed and directed Fitness, Nutrition, Wellness, and Sports Performance programs at such medical facilities as the John Ochsner Heart and Vascular Institute, Ochsner Health Systems, East Jefferson General Hospitals’ Mackie Shilstone Fitness Principle, and Wellness programs at St. Charles Parish Hospital.

Mackie is President of Mackie Shilstone Inc., a sports performance, fitness, and wellness consulting company, with clients such as Serena Williams, chosen as “Female Athlete of the Decade” by the Associated Press; and the Office of the Commissioner of Major League Baseball’s Umpire Medical Services Division.

With a Master of Arts degree and Master of Business Administration, Mackie has served as a Clinical Instructor of Public Health and Preventative Medicine at Louisiana State Health Sciences Center, Adjunct Instructor in the School of Allied Health at Nicholls State University, and Adjunct Professor at the A. B. Freeman School of Business at Tulane University.

Mackie has also served as a special advisor to the United States Olympic Committee on Sports Nutrition, and on the Louisiana Governor’s Council on Physical Fitness and Sports.

Mackie’s column can be found on WWLTV.com/health – along with his weekly TV segment – Workout Wednesday. Mackie’s podcast – Maximum Wellness – is available on Itunes, Spotify, and Android sites.

His most recent book, Stop Renting Your Health—Own It: A Three Step Approach, was published in January 2012, and outlines the same unique, science-based approach Mackie uses with celebrities and sports professionals to improve health, performance and image.

Mackie’s previous book, Body Plan for Kids, is a comprehensive guide for parents to gain control of their child’s weight. It is the first book of its kind to offer specific strategies for eating healthy, getting fit and increasing self-esteem targeted at 8-12-year-olds.

His other books include Lean & Hard: The Body You’ve Always Wanted in Just 24 Workouts, the ultimate strength-building workout for a powerful muscular physique; The Fat Burning Bible, 28 days of foods, supplements, and workouts that help you lose weight, (January 2005); Lose Your Love Handles: A 3-Step Program to Streamline Your Waist in Only 30 Days (Perigee 2001); Maximum Energy for Life (John Wiley 2003), and Feelin’ Good About Fitness (Pelican Publishing, 1986).

Mackie has written articles for health and fitness publications including “Muscle and Body” Magazine, the American Medical Athletic Association Quarterly, The Physiologist, Nola.com, and the Washington Post’s Fantasy League website – The League.

In January 2020, Mackie was appointed to the Advisory Board, Tulane University School of Professional Development, Department of Kinesiology.

In April of 2022 Mackie was inducted into the Tulane University Athletics Hall of Fame, as a member of the 1973 Tulane Football Team.

In September of 2022 Mackie was the featured speaker on opening day of the USPTA World Conference in New Orleans. The on-court demonstration featured was "Increasing the Impact & Effectiveness of the Most Devastating Tennis Weapon, The Serve."