[2] Hillcourt was a prolific writer and teacher in the areas of woodcraft, troop and patrol structure, and training; his written works include three editions of the BSA's official Boy Scout Handbook, with over 12.6 million copies printed, other Scouting-related books and numerous magazine articles.

Hillcourt developed and promoted the American adaptation of the Wood Badge adult Scout leader training program.

[5] After deciding to experience Scouting around the world and to return home with the best ideas, Hillcourt worked his way through Europe and England and then arrived in the United States in February 1926.

[5] Hillcourt worked at a BSA camp at Bear Mountain in Harriman State Park, New York, in 1926 where he became an instructor in American Indian dance.

Each monthly issue included a page on advancement and Scoutcraft, outdoor Scouting skills, and included his signature superimposed over the two green bars that are the emblem of the patrol leader, which led to his moniker "Green Bar Bill" and its adoption as the logo of his regular Boys' Life column.

[2][5] Hillcourt was tasked to write a new manual for Scoutmasters in 1934 and worked with his good friend and colleague E. Urner Goodman, the national program director of the BSA.

He and his wife moved to a house in Mendham Borough, New Jersey, to be near Schiff Scout Reservation,[10] the BSA's national training center, so he could be in place to put his theories to a practical test.

After World War II, Wood Badge was revived and Hillcourt was the Scoutmaster for a test course begun on July 31, 1948, at Schiff and the first standard course at Philmont Scout Ranch.

[4] Many Scouters, including Hillcourt, were critical of the new program changes, exclaiming that the de-emphasis on traditional outdoor skills had taken the "outing out of Scouting".

[3][note 1] In 1980, the BSA presented Hillcourt with their highest national honor, the Silver Buffalo Award and he was cited as "The Voice of Scouting".

"[2] In the last 12 months of 1985, he traveled to Dallas, Washington, Knoxville, Houston, San Francisco, Cleveland, Los Angeles, and other cities.

And then, of course, in the middle of the times, he continued to camp in the different events that took place during his campaign and did not fail to make a presence with his uninterrupted record, with the Jamboree.

Travel and appearances at Scouting events both local and worldwide were part of his routine until he died, for which he was referred to as Scoutmaster to the World.

He is buried with his wife Grace in St. Joseph's Cemetery (Row 8, Block I) in Mendham Borough, New Jersey, United States.

The grave lies within the geographic scope of the Patriots Path Council near Schiff Scout Reservation at coordinates 40°46′32″N 74°36′09″W / 40.7755°N 74.6024°W / 40.7755; -74.6024, where he lived for many years.