[3][4] He served as president of Moncrief Oil, and was a billionaire member of the 2006 Forbes 400, with an estimated net worth of US$1 billion.

[5][9] In 1931, at the age of ten, Moncrief witnessed the opening of a gusher oil well at Gregg County, a joint venture between his father and John E. Farrell.

[10] In 1972, Moncrief acquired one-third of the natural gas field Madden Deep in Wyoming, which proved very profitable.

[5] On January 4, 1996, Moncrief and Montex settled with the IRS by agreeing to pay $23 million "for deficiencies in income, excise and gift taxes for taxable periods from Jan. 1, 1989, through Aug. 31, 1994.

If you had told me that 64 IRS agents would storm my office, with sidearms holstered and boot heels trampling my civil rights and my business reputation, I wouldn't have believed you.

[10] In September 2009, Moncrief bought a 10% stake in McMoRan Exploration Co.'s Davy Jones oil well off the Louisiana coast.

[4] Throughout his career, Moncrief strictly adhered to rules originally held by his father, to operate only through sole proprietorships and never go public.

[3] In a 1998 article for FW Weekly, journalist P. A. Humphrey reported that family members, former employees and acquaintances had variously described Moncrief as "arrogant, controlling, opinionated, short-tempered, headstrong, [and] unyielding.

"[5] Moncrief was a founding member of the Shady Oaks Country Club in Fort Worth, Texas, and a close friend of professional golfer Ben Hogan.