As a kid, Steven Spielberg charged $0.25 admission for 8-mm adventure movies he made with friends.

His sister often sold popcorn at the screenings. Some flicks featured train wrecks staged with his toy trains. The factors that would drive Spielberg’s career and make him one of Hollywood’s most successful directors were then clear: any story, no matter how engaging and artfully shot, required a sharp eye on the bottom line.

Friends soon called him “Cecil B. deSpielberg” -- homage to the legendary director and Academy Award-winning film producer Cecil B. DeMille. Like many kids, Spielberg followed his passion to the exclusion of minor annoyances like school, giving his career an ironic twist: Several film schools rejected him because he had poor grades. He dropped out of Long Beach State University, a so-so school close to LA’s port, to work full-time at Universal.

The rest, as they like to say in Hollywood, is history -- and what a history. In 1974, Pauline Kael, the notoriously cranky movie critic at The New Yorker, called The Sugarland Express, Spielberg’s first feature film, “one of the most phenomenal directorial debuts in the history of movies.”

Spielberg established himself as a box-office winner the following year with Jaws, a fish story that gave some a case of thalassophobia,or abnormal fear of the ocean. At 28, his career took off. Spielberg’s credits include some of the most popular (and highly profitable) movies to come out of Hollywood in a generation: Close Encounters of the Third Kind, Raiders of the Lost Ark, The Color Purple, Who Framed Roger Rabbit, Back to the Future, and Jurassic Park. Spielberg also has an interest in World War II, directing Saving Private Ryan and Schindler’s List.

Spielberg quickly established himself as more than a mere artist, pontificating on arcane points of movie-making that would bear a cross-eyed cow. His movies combined critical success and profitability. Spielberg makes extraordinary use of special effects, using eye-popping images to grab the audience and advance the story -- think of the boulder chasing Harrison Ford in the opening scenes of Raiders of the Lost Ark.

Others dabbled with product placement in movies, but Spielberg demonstrated its selling power with the use of Reese’s Pieces in E.T. Sales reportedly rose 65% after Elliot, the all-American suburban kid, used the treat to establish his good intentions with the extraterrestrial creature.

Like any entrepreneur, Spielberg asked a basic question: Why work for someone else?

In 1994, Spielberg launched DreamWorks SKG with Jeffrey Katzenberg and David Geffen. It produced or distributed about 10 movies with box-office grosses totaling more than $100 million each. In 2005, the founders sold the company to Viacom (VIA) for about $1.6 billion.

DreamWorks SKG spun off DreamWorks Animation (DWA) in 2004, pricing 29 million shares at $28 each in an initial public offering. The company uses computer-generated images to develop a string of hits, including Kung Fu Panda, Bee Movie, Shrek, and Shrek 2, the highest-grossing animated film in history. Its films are distributed by Paramount.

In August 2009, Spielberg and Stacey Snider announced that they’d lined up $825 million needed to launch a new studio. The money came from Reliance ADA Group, a conglomerate in India. Spielberg also received debt financing from major banks, including Israel Discount Bank, Wells Fargo (WFC) and Bank of America (BAC). The new studio plans to shoot about six movies a year to be distributed by Walt Disney (DIS).

The early outlook is good. Spielberg has secured the rights to film the life of civil rights leader Martin Luther King and plans to remake Harvey, the 1950s hit that featured James Stewart and his best friend, a giant rabbit.

In 2008, Forbes magazine estimated Spielberg’s wealth at $3.1 billion. This suggests he’s a true entrepreneur, making movies because it’s his passion and making money because he’s smart. All those studio deals give him more freedom to follow his heart and shout, “Action!”

Not bad, for a college dropout.