He later earned his LLB from the University of Washington in 1958, where he served as Editor in Chief of the Washington Law Review and Order of the Coif, both of which arc academic excellence honors. He received his LLM from Harvard Law School in 1963, where he was a Teaching Fellow for two years.

Professor Johanson has been on the University of Texas faculty since 1963, where he has been selected by the students to receive the Teaching Excellence Award on four occasions. He has taught as visiting professor at several other law schools, including Georgetown, North Carolina, Utah, the University of Washington, UCLA, and Chicago.

Johanson is active in several professional groups, including the American College of Trust & Estate Counsel, the American College of Tax Counsel, and the International Academy of Trust and Estate Law. A former member of the Texas State Bar Real Estate, Probate and Trust Law Counsel, he is a member of the Texas, Washington (state) and American Bar Associations. He is also Of Counsel to the Houston law firm of Vinson & Elkins.

Professor Johanson is a frequent lecturer at Continuing Legal Education programs and tax conferences and is the author of numerous articles on estate planning and will and trust drafting. He is the author of Johanson’s Texas Probate Code Annotated and the co-author (with Jesse Dukeminier) of Wills, Trusts & Estates, a law school casebook that has been adopted at over 120 American law schools, He has received numerous other awards over his lengthy career.

In 1997, Professor Johanson was selected as the recipient of the Treat Award for Excellence presented by the National College of Probate Judges which is awarded annually to “an individual who has made a significant contribution to the improvement of the law or judicial administration in probate or related fields.”