Dr. Gargalionis was born and raised in Tripoli, Greece, and earned his medical degree from the School of Medicine at the National and Kapodistrian University of Athens (NKUA).

In 2015, he completed his specialization in Medical Biopathology/Laboratory Medicine. He also holds a Master's degree in "Molecular and Applied Physiology" and received his doctorate from the Department of Biological Chemistry at the NKUA School of Medicine, funded by a scholarship from the Hellenic Society of Digestive Oncology.

Dr. Gargalionis conducted postdoctoral research funded by the State Scholarships Foundation. He has worked as a physician at the General Panarkadian Hospital of Tripoli, the General Hospital of Athens "LAIKO," and Eginition University Hospital, where he also served as part of the teaching faculty. In 2024, Dr. Gargalionis joined the NKUA School of Medicine as an Assistant Professor of Clinical Biochemistry and Medical Chemistry. Currently, he divides his time between teaching, research, and clinical work at the Department of Clinical Biochemistry at Attikon University Hospital. His clinical responsibilities include routine biochemical diagnostics and monitoring of patients, as well as performing diagnostic serum/urine protein electrophoresis and immunofixation.

Dr. Gargalionis teaches biochemistry to undergraduate students at the NKUA School of Medicine, the NKUA School of Dentistry, and in the NKUA Medical Degree (English Program). He also lectures on biochemistry and cancer mechanobiology in various postgraduate programs.

His primary research focus lies in studying the molecular mechanisms driven by mechanical forces in cancer development. In 2023, he was recognized by the World Journal of Clinical Oncology as one of the most influential and productive scientists globally in the field of cancer mechanotransduction. Dr. Gargalionis has contributed to numerous research projects and has received several research awards. He has reviewed over 50 peer-reviewed articles, served as a Guest Editor, and is currently a Section Board Member for Molecular Biology at the International Journal of Molecular Sciences. With over 60 publications indexed in PubMed, his work has garnered more than 1,400 citations, earning him an h-index of 22. He has also co-authored conference abstracts and delivered invited lectures at national and international conferences. Additionally, he serves on the administrative boards of the Hellenic Society of Medical Biopathology/Laboratory Medicine and the Hellenic Society of Medical Biochemistry.