H Henderson was born on July 25, 1922, in Seymour, Indiana, a city in Jackson County in southern Indiana. He came of age in a period when American lawyers were admitted to practice through individual state bars and federal courts, a structure that later governed his admissions in Indiana, Iowa, and Nebraska.
He received a Bachelor of Science degree from Purdue University in 1947. Purdue was founded in 1869 as a land-grant institution under the Morrill Act, and its mission from the beginning centered on agriculture and engineering education. Its first classes were held in West Lafayette, Indiana, in 1874.
He later received a Bachelor of Laws degree from Indiana University. The law school, founded in 1842, was then known as the Indiana University School of Law in Bloomington. It is recognized as the first state law school in the Midwest, and it was renamed the Maurer School of Law in 2008.
Henderson was admitted to the Indiana bar in 1954 and to the Iowa bar in 1957. His admissions extended to the United States District Courts for the Northern and Southern Districts of Iowa and to the United States Court of Appeals for the Eighth Circuit. He was admitted before the United States Supreme Court in 1964, and he was admitted in Nebraska in 1966. In the following years he was admitted before the Court of Appeals for the Seventh and Tenth Circuits in 1971, the Fifth Circuit in 1972, and the Court of Appeals for the Federal Circuit in 1982. He also practiced before the United States Patent and Trademark Office.
He was a partner of Henderson & Sturm, a law firm in Des Moines, Iowa, the state capital and the seat of Polk County. His practice was described as limited exclusively to patent, trademark, copyright, and unfair competition law, along with federal trial practice. Intellectual property work of this kind required registration and practice before the Patent and Trademark Office, the federal agency that examines patent applications and registers trademarks, and the firm's patent work is reflected in public patent records.
Henderson belonged to the Iowa State Bar Association, the oldest voluntary state bar association in the United States, which was organized in May 1874 at the Polk County courthouse in Des Moines. He was also a member of the Nebraska State Bar Association and the American Bar Association, the national professional organization of American lawyers, founded in 1878.
He was active in the Iowa Patent Law Association, serving as its president. The association represented patent practitioners in Iowa, a specialty that corresponded to his practice in patent and related intellectual property law.
