Mr. Kato is active not only in the courts, but also in academia. As an academic, Mr. Kato has written papers in various fields of private law, while also teaching the Japanese Civil Code at university. As a practicing lawyer, he has substantial experience in very complex business cases concerning civil, commercial, patent, labor and tax laws. Mr. Kato revels in handling　complex cases in which a judge has difficulty in making findings of fact, especially those cases in which a client is appealing a prior ruling adverse to the client.

A brief summary of Mr. Kato's extensive legal career follows. In the field of academia, Mr. Kato has lectured as a professor at Nagoya University's Graduate School of Law, a professor of law at Sophia University School of Law, a professor of law at Nagoya Gakuin University, a visiting fellow at Harvard University and the University of London, and a visiting professor at the University of Hawaii, University of Washington, Columbia University and Beijing University. In the field of legislation, Mr. Kato contributed significantly to various governmental bodies, including the Civil Law Subcommittee of the Legislative Council　of the Ministry of Justice and the National Bar Examination Committee. He also has been engaged in framing significant conventions in the international business world, including the UNIDROIT Convention on International Financial Leasing and the UNIDROIT Convention on International Factoring.

Mr. Kato is considered to be one of Japan's leading civil code scholars. He has authored a series of five civil code textbooks titled "Contemporary Civil Code System of Japan". In addition, he has authored books and articles in the areas of commercial law, civil procedure, international transactions, intellectual property, labor, administration, tax, environmental law, American law and Chinese law. Mr. Kato's works on product liability, torts, unjust enrichment and financial leasing contracts are regarded as the definitive treatises in Japan.

As a renowned Civil Code scholar, Mr. Kato worked with the Ministry of Justice staff during the early stages of the process to amend Japan's Civil Code. However, due to a difference of opinion, Mr. Kato elected to discontinue his involvement with the Ministry of Justice until the amended Civil Code of Japan was promulgated in June 2017. Mr. Kato was critical of the ideas of the Ministry of Justice in his two books titled "Civil Code (Obligatory Law) Amendment—Wandering Japanese Civil Code" and "Day of Civil Code Amendment Presses". At the same time, he and his fellow scholars published two books in which they issued their own proposal for the recodification of the Japanese Civil Code. These books were entitled "A Proposal of Japanese Civil Code Book I—Proposed Provisions and Amendment Reasons" and "An Overall Amendment of the Japanese Civil Code—By the People, Lawyers and Academics".
These proposals, particularly those contained in the first book, garnered international attention and were translated into Simplified Chinese by Beijing University Publishers in Mainland China and into Traditional Chinese by Angel Publishing Co., Ltd. in Taiwan. In addition, Mr. Kato gave a lecture on the history of codifications of the world at a symposium held in the Parliament of Mongolia.

Taking advantage of this experience, Mr. Kato’s practice encompasses the entire civil law with a particular focus on product liability, compensation law for damages, unjust enrichment, leasing, trust law, and Chinese civil law (in which fields he has authored many books and theses) as well as complex cases of civil and commercial litigation.