In 1867 he worked at the Rock Island Arsenal as a stone-cutter, and in the same year he went to Wyoming, where he cut stone for Union Pacific bridges, forty miles west of Cheyenne.

March 17, 1868, then a lonely spot in the wilderness, now the site of Stone City, Iowa, a prosperous community in the late 19th century that added great wealth to the state and to Jones County, built, as its name indicates, on the business inaugurated by Mr. Green when he opened the Champion quarries.

1896 records indicate 1,000 men employed among the city's quarries, carving 160,000 loads of stone in a single year with a market value of 3.75 million dollars.

With his financial success and a keen eye for marketing, Green soon envisioned a city made entirely of stone to accommodate the growing population (from 60 to almost 500 by 1880).

He was the first in the United States to employ hydraulic power for stripping quarries, and he was also the first to load large holes with several hundred pounds of black powder, to shake the hills and loosen thousands of tons of stone at one blast.