Around 1930, Vilhelm Jensen performed a small act of reinvention. He anglicized his first name to William, translated 'Bjerregaard' — which means hill-court in Danish — into its English equivalent, and dropped 'Jensen' entirely. William Hillcourt. The new name was both practical and symbolic: he was making himself American, the same way he had made himself a Scout. He had joined the Danish Scouting movement in 1910 at age ten, attended the 1st World Scout Jamboree in London in 1920 where he first met Baden-Powell, and worked his way up to national instructor and editor of the Danish Scouting journal. By the time he arrived in the United States and was hired by the Boy Scouts of America's national office, he had been living the program for nearly two decades.

The story of how Hillcourt transformed American Scouting begins with an elevator ride. He met BSA Chief Scout Executive James E. West in the elevator of the BSA national office, and West asked him what he thought of Scouting in the United States. Hillcourt thought carefully, then sent West an 18-page memo laying out the problems — chiefly, the lack of patrol structure and leadership development. His recommendation: write a dedicated handbook for patrol leaders, and make sure it was written by someone who had actually been a patrol leader and a Scoutmaster. West hired him to write exactly that. The Handbook for Patrol Leaders was published in 1929. From there, Hillcourt went on to write three editions of the official Boy Scout Handbook — the sixth edition, completed in time for the BSA's 50th anniversary in 1960, is considered among his finest work.

In 1935, Hillcourt founded Troop 1 of Mendham, New Jersey, chartered directly to the National Council of the BSA. His reason was deliberately experimental: he wanted a real troop to test and validate his theories about patrol structure and youth leadership. He served as Scoutmaster for 16 years. The troop was his laboratory, and the New Jersey countryside around Mendham was its classroom. Hillcourt's connection to Mendham is why his location coordinates fall here — this quiet Morris County town is where the man who wrote the Scout handbook put his ideas into practice with actual boys, year after year. The BSA national office moved from New York City to North Brunswick, New Jersey, in 1954, and Hillcourt moved with it, remaining active in Scouting until his death at 92.

For decades, Hillcourt wrote a column in Scouting magazine under the byline 'Patrol Leader Green Bar Bill' — the green bars on a patrol leader's uniform giving him his enduring nickname. He traveled to South America, Japan, Europe, and beyond, teaching Wood Badge courses, attending World Scout Jamborees, and training scout leaders. In 1980, the BSA gave him its highest honor, the Silver Buffalo Award, citing him as 'The Voice of Scouting.' In 1985, the World Organization of the Scout Movement awarded him the Bronze Wolf — Scouting's international highest honor — and Scouting magazine called him 'the foremost influence on development of the Boy Scouting program.' He attended Scouting events locally and worldwide until the end of his life, never losing the habit he formed as a ten-year-old in Aarhus.