Potential conflict of interest: Nothing to report. TO THE EDITOR: It is with a deep sense of loss and a heavy heart that we learned of the unexpected passing of Dr. Hugo R. Rosen at the very end of 2021. I invite you to review his obituary to learn of his training, career path, and his numerous accomplishments (https://www.dignitymemorial.com/obituaries/glendale‐ca/hugo‐rosen‐10509391), but my intent is to relay a personal story on the impact of his mentorship over 2 decades. Hugo’s family was Jewish and emigrated from Cuba to Miami. Spanish was his native tongue, and his Cuban identity was very important to him. It was not uncommon to see Hugo wearing a guayabera and a fedora, often with a Boston Celtics jersey underneath. Hugo’s interest in hepatology was sparked after being assigned to a weeklong elective during his fourth year of medical school. He tells the story of thinking the rotation was initially in hematology and then herpetology (study of amphibians and reptiles). At the time, hepatitis C virus (HCV) was only known as non‐A or non‐B viral hepatitis, there were little to no therapies for chronic liver disease, and liver transplantation was only being performed at a handful of programs in the United States. During this weeklong elective, he fell in love with the field of hepatology and decided to make it his career. Hugo did transformative translational research focused on filling in the gaps of human disease. He focused on understanding the genetics and the immune mechanisms that mediate phenotypes of disease. He asked the fundamental question, “Why do people with the same liver disease develop such different outcomes?” Hugo’s early research focused on trying to understand why some patients with HCV did well and others required liver transplantation and why some developed severe recurrent HCV after liver transplantation and others did not. Going into the field of transplant hepatology was not a common path when I was applying for a gastroenterology/hepatology fellowship 2 decades ago. My mentor at the time recommended that I go to Oregon and work with this “young, up‐and‐coming hepatologist” there named Hugo Rosen. During my interview with Hugo, I immediately recognized how Hugo would be an important mentor to me in my pursuit of a career in transplant hepatology, and I know I am not alone among the trainees and young faculty who have met, been mentored by, and looked up to Hugo as a role model over the decades. I had no background in basic science or immunology, but Hugo was one who believed in people and invested his effort so broadly, and he welcomed me into his laboratory where I learned how to culture T cells and perform enzyme‐linked immune absorbent spot assays and flow cytometry. He would soon give me the nickname of “Skippy” and later “Jaybird.” I worked closely with Hugo through fellowship training and as a junior faculty member at Oregon Health & Science University. When Hugo was offered the Chief of Gastroenterology/Hepatology at the University of Colorado in 2005, he invited me to go with him. I immediately agreed and have not had any regret. In Colorado, Hugo continued as my mentor in the laboratory as I pursued research on HCV‐specific T cell responses in patients undergoing antiviral therapy. Outside the laboratory, I published on HCV recurrence after liver transplantation with Hugo. I became an expert on treating HCV after liver transplantation with pegylated interferon and ribavirin and direct‐acting antivirals with co‐mentorship from Greg Everson. Hugo had a special gift for identifying people’s talents, helping them see those talents and guiding them toward success. Although I enjoyed my time in the laboratory and learned a lot about immunology and translational research, I knew I was not going to be a physician‐scientist like Hugo. My talents were better served taking care of patients, so with Hugo’s support and encouragement, I pivoted out of the laboratories and in 2008 assumed the clinical position of Medical Director of Liver Transplantation. As a young trainee and junior faculty, I saw in Hugo someone who shared the same excitement I had for the field of hepatology and liver transplantation. Hugo taught all of us to be avid learners, follow our passions, and pursue the clinical and scientific questions that you, rather than he, found interesting. Hugo valued those who were hard working and possessed a “fire in their belly” to be a world expert on what they were studying. He also valued humility. Hugo was always accessible to me, an aspect he knew was critical in being a successful mentor. Mentorship from Hugo was not simply career development, but personal development. Hugo was truly invested in me and thus the relationship became personal by default. Hugo’s mentees became part of his own family. I have a photo of Hugo holding my daughter Olivia just weeks after her birth in 2003, which I keep on my desk. When we moved to Denver a couple years later, Hugo and his wife Bonnie took my family into their home while we looked for a place to live. It was wonderful to see Hugo as a beloved husband to Bonnie and proud father to his 3 children, Rachel, Nicholas, and Leah. When Hugo left Colorado to be the Chair of Medicine at University of Southern California in 2018, our mentor‐mentee relationship made a required transition as well. It was time for me to be out of his shadow and to spread my own wings in leading the hepatology section and liver transplantation program at University of Colorado without him. He left me adequately prepared. Although this tale has been deeply personal, I know that many of you have had similar experiences. Hugo was the type of person whose warmth and affection impacted everyone he met, even casually. With the passing of Hugo Rosen, the fields of hepatology and liver transplantation have lost one of the great ones. Hugo was at the pinnacle of his career when he died, having already displayed a lifetime of achievements in medical research and clinical leadership. I feel incredibly fortunate and grateful to have had the opportunity to be under his mentorship for nearly 2 decades. Hugo was kind, generous, and devoted to me as well as to the many others he mentored, just as he was devoted to his family and his many friends. He was a lovely person and will be missed dearly by all who knew him. But I know his legacy will live on in all of us.