Takaji Wakita received his medical degree in 1983 from Nagoya University, Nagoya, Japan. He was then trained in the clinic for 5 years. He obtained his PhD in Internal Medicine III at Nagoya University in 1992 for a thesis entitled "Detection of pre-C and core region mutants of hepatitis B virus in chronic hepatitis B carriers".
He received postdoctoral training at Molecular Hepatology Laboratory (Dr. Jack Wands' Lab), Massachusetts General Hospital Cancer Center, Boston between 1992 and 1995, work commenced on antisense inhibition of hepatitis C virus. In 1995, he moved to Department of Microbiology, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan, and then moved to Tokyo Metropolitan Institute for Neuroscience as a Principal Investigator in 1998. In 2006, he moved to National Institute of Infectious Diseases, Tokyo, Japan, and was appointed as a Director of Department of Virology II.
In 2015, he was appointed as a Deputy Director-General and then in 2018 as a Director-General of National Institute of Infectious Diseases. His major research interests include; Infection and replication models of hepatitis C virus, Pathogenesis of hepatitis viruses, and Novel therapeutics and vaccine development for hepatitis virus infections. He received Hideyo Noguchi Memorial Medical Award in 2008, and Oda Prize (awarded by the Japanese Society of Hepatology) in 2009.