Here is a selection of Phds and other advanced degree holders who have made it outside of academia. More to be added in future.

Vartan Gregorian, (PhD, Stanford University, 1964): Gregorian is the president of the Carnegie Corporation. Before heading the Carnegie Corporation, he served first as the president of the New York Library and then as president of Brown University. In 1998, President Clinton awarded him the National Humanities Medal.

Lucy Killea, (PhD, University of California, San Diego 1975): In California, Killea is well-known for her eighteen years of service as an elected official, serving on the San Diego City Council (1978-82); in the California State Assembly (1982-89); and in the State Senate (1989-96).

Barbara Mertz a.k.a Elizabeth Peters and Barbara Michaels (PhD, University of Chicago, 1952): An Egyptologist, Mertz is an award-winning murder mystery writer whose works have dominated the New York Times best-seller list for decades. In 1998, she was named a Grandmaster by the Mystery Writers of America.

Sharan Newman (currently a doctoral student at the University of California, Santa Barbara): A student of medieval history, Newman is the author of a series of murder mysteries set in medieval France. Her books have won numerous awards, among them the Macavity Best First Novel award for Death comes as Epiphany in 1994 and the first Herodotus Award for Cursed in Blood in 1999.

Sarah Paretsky (PhD, University of Chicago, 1975): After receiving her doctorate in history, Paretsky recognized the "complete lack of academic jobs for historians [and she]...bowed to the inevitable...and got an MBA from the University of Chicago." She worked as a marketing manager for an insurance company for ten years before turning to writing. Today, she is an award-winning novelist whose popular murder mysteries featuring V.I. Warshawski have been made into a film starring Kathleen Turner.

Bernice Johnson Reagon, (PhD, Howard University, 1975): An African-American historian, Johnson is the founder of Sweet Honey in the Rock, a Grammy-winning African-American a capella group. Her historical scholarship has been informed by her work as a political activist. In 1989, she received a MacArthur "Genius" Fellowship.

Geoffrey Moore, Managing Director, tcg Advisors
PhD in medieval and Renaissance literature, University of Washington. His books include Living On The Fault Line. Business Week writes about how this ex lit professor turned a sweeping curiosity into $15,000-a-day corporate teaching gigs.

Lisa Drakeman, President and CEO, Genmab AS
MA, American History and PhD, Religion, Princeton. Read about Mrs. Drakeman's transition from religion professor to biotech CEO in the Wall Street Journal (subscription required).

Patrick Byrne, CEO, Overstock.com
PhD in Philosophy, Stanford.

Tom and Ray Magliozzi, The Car Talk Guys
Ray admits to an MIT degree in humanities and science. "MIT is known for its humanities program. After all, with a name like Massachusetts Institute of Technology, you know they must have a splendid humanities department."

Tom earned a PhD in chemical engineering at Boston University and writes that "I put on the robes, they called me 'Doctor' (for one day), and I got a job as a real college professor. It was good. For about eight years. But suddenly (actually it happened gradually, but I didn't know it) it was over. I reached (through deep thought, meditation and prayer) a miraculous epiphany: Teaching sucks."

Martin Luther King, Jr.
PhD, Theology, Boston University. Live cam of Marsh Plaza and MLK memorial. Fittingly, BU was the first university in America to award PhDs to women (1877).

Genevieve Bell, Corporate Anthropologist, Intel
Bell's Stanford Anthropology PhD equips her to study the ethnography of consumer spaces. Her research helps Intel invent technology that solves problems.

Tadatoshi Akiba - mayor of Hiroshima, Japan. He has a PhD in mathematics from the Massachusetts Institute of Technology.

Ion Barbu - Romanian poet, pen name of Dan Barbilian, a mathematician

Lewis Carroll - Charles Lutwidge Dodgson, better known by the pen name Lewis Carroll, was an English author, mathematician, logician, Anglican clergyman, and photographer. Although not the most studious of students, his talent as a mathematician won him the Christ Church Mathematical Lectureship, which he continued to hold for twenty-six years.

Ahmed Chalabi - Iraqi politician. He has a PhD in mathematics from the University of Chicago.

Pasquale del Pezzo - Italian mathematician, later mayor of Naples and senator in the Kingdom of Naples.

Éamon de Valera - first president of the Irish Republic, was a professor of mathematics before entering politics.

Omar Khayyam - Persian poet, wrote several books on algebra and geometry.

Emanuel Lasker - world chess champion from 1894 to 1921, received his doctorate in mathematics under Hilbert.

James Harris Simons - American investment advisor, billionaire, and philanthropist. He has a PhD in mathematics from the University of California, Berkeley and is the co-inventor of Chern-Simons theory.

The Simpsons - check out here, and for the mathematical background of the writers.

Paul Painleve, President of France in the early 20th century, and one of the first passengers of the Wright Brothers. A ringer: he had a distinguished mathematical career.

Christopher Wren , the architect of St. Paul's Cathedral in London.

Edmund Husserl, the "Father of Phenomenology," PhD in 1883 from Vienna.

Frank Ryan, star quarterback from the Cleveland Browns in the sixties. PhD from Rice.

Ted Kaczinski, PhD in mathematics from University of Michigan. Kaczinski worked at UC Berkeley for some time and published papers in complex variables before retreating to the woods and becoming the infamous "unabomber."

Phil Gramm - US Senator (University of Georgia, PhD, Economics)

Dick Armey - US Congressman (University of Oklahoma, PhD, Economics)

George Schultz - Former US Secretary of State (Princeton; MIT Ph.D, Economics)

John Snow - US Secretary of Treasury (University of Virginia, PhD, Economics)

Kenneth Lay - Former CEO of Enron (University of Houston, PhD, Economics)

Manmohan Singh - Prime Minister of India (Oxford University, Ph.D., Economics)

Ernesto Zedillo - Former President of Mexico (Yale University, Ph.D., Economics)

Carlos Salinas de Gortari - Former President of Mexico (Harvard University, Ph.D., Economics)

Janez Drnovsek - Prime Minister of Slovenia (University of Maribor, Ph.D., Economics)

Anatoly Chubais - Former Deputy Prime Minister of Russia (St. Petersburg Institute, Ph.D., Economics)

Leszek Balcerowicz - President of the National Bank of Poland (Warsaw School of Economics, Ph.D., Economics)

Abdullah Gül - Deputy Prime Minister of Turkey (Istanbul University, Ph.D., Economics)

Duck-Woo Nam - Former Prime Minister of South Korea (Oklahoma State University, Ph.D., Economics)

Philip Austin - President of University of Connecticut (Michigan State, Ph.D., Economics)

Yuliya Tymoshenko - Prime Minister of Ukraine (Dnipropetrovs'k State University, Ph.D., Economics)

Viktor Yuschenko - President of Ukraine (Ternopil Financial and Economic Institute, Ph.D., Economics)

Sadie Tanner Mossell Alexander - First black woman to be awarded a Ph.D. in the United States (and it was in economics from the University of Pennsylvania).

Gordon Brown - University of Edinburgh, History Phd, 1982. Prime Minister of Britain.

Condoleezza Rice - University of Colorado, Political Science Phd, 1981. US Secretary of State.

Sources:
http://www.beyondacademe.com/outsidethebox.htm
http://www.ironstring.com/sellout/philologists/flown_philologists.shtml
http://en.wikipedia.org/wiki/List_of_famous_persons_initially_trained_in...
http://www.loyola.edu/mathsci/resources/famousnonmathematicians.htm
http://www.marietta.edu/~ema/econ/famous.html