Macklem taught math and science at Tri-West Hendricks Jr/Sr High School in Lizton, IN and at Elkhart Memorial High School in Elkhart, IN. He has also taught calculus at Bethel College in Mishawaka, IN. For his high school work, Macklem received a Lilly Teacher Creativity Fellowship and a Milken National Educator Award.
Macklem holds a BS in mathematics and biology from the University of Michigan and an MA in History and Philosophy of Science from the University of Notre Dame. He is currently working on a doctoral dissertation on the role of history and philosophy of science in K-12 science education. He holds Indiana teaching certifications in mathematics, biology, physical science, and chemistry.