When cameraman Garrett Brown chased Sylvester Stallone up the Art Museum stairs in 1975 to bag the signature shot of Rocky (1976), Philadelphia was not on Hollywood's radar.

"We hadn't a clue how to host a movie," recalls Brown, a longtime resident of Society Hill. Directors complained of city ineptitude. There was no agency to scout locations, issue permits, or announce that electricians were needed. "Filming here was eccentric and inconsistent until Sharon came along and sorted us out."

That would be Sharon Pinkenson, since 1992 the executive director of the Greater Philadelphia Film Office, which is celebrating its silver anniversary.

On Sunday, screenwriters will gather at the new Sun Center Studios in Chester Township to share scripts set in Philadelphia. At night, the studio will host a birthday bash honoring the office, which has brought to town the likes of Jennifer Aniston and Owen Wilson, Tom Hanks and Denzel Washington.

The story of the birth, near death, and turnaround of Philadelphia's film office has many heroes, including R.C. Staab, film commissioner in January 1986, when it opened for business. But mostly, says Staab, now a newspaper executive in California, it is the story of how Pinkenson, a former dental hygienist with a passing resemblance to Goldie Hawn, scooped up the fumble and ran with the ball.

"Philadelphia is a movie town today," Pinkenson says, "and that 'cool' factor may be the most important accomplishment of my career."

In 1986 the film office scored one movie, the department-store fantasia Mannequin, accounting for an estimated $6 million spent in the region. In 2009, 17 movies and TV shows were made here, including M. Night Shyamalan's The Last Airbender, James L. Brooks' How Do You Know, and the A&E series Teach with Tony Danza. Direct spending was $286 million.

"In my years as an elected official there's probably been no better return on investment than the film office," says Gov. Rendell, who appointed Pinkenson when he was mayor of Philadelphia.

The film office was born of adversity. The city had an image problem in 1984 when director Alan Parker came to make Birdy and butted heads with unions and city officials.

"Parker publicly damned Philly as a film location," says Staab, who had been running the state film commission. "This was also the era of the MOVE bombing. The thinking was that a film office was a small investment that might yield big returns."

"In 1986, the City of Philadelphia officially went into the film business, proactive rather than passive," says Staab. With Mayor W. Wilson Goode's blessing, it had an annual budget of $160,000 and a staff of three.

The high point of Staab's tenure was landing the film Clean and Sober (1988). The low point was the '87 stock market crash and the city fiscal crisis, which resulted in budget cuts, recalls Joan Gerstle, a film office staffer from its inception through 2007.

First Staab and then his replacement decamped, leaving Gerstle to man the phones and airport purchasing manager Charlie Isdell to moonlight as acting director. The momentum generated by Staab was lost. Even worse, a Hollywood producer was bad-mouthing Philadelphia unions as "uncooperative."

Meanwhile, the well-funded Chicago and Pittsburgh film offices were scouting locations in their cities for movies set in Philadelphia.

"You could argue there were people better qualified than Sharon to run the film office," says Staab. Rendell thought otherwise.

In 1992, Pinkenson approached the mayor. The gal with the mane of blond curls had been a dental hygienist, co-owner of Plage Tahiti boutique, and a costumer with a handful of credits on B-list films such as Mannequin Two, filmed at Wanamakers. She was a 44-year-old graduate of Girls High and Temple University, mother of a high school senior. (She later wed businessman Joe Weiss.)

"I hired Sharon," says Rendell, "one, because she had experience in the industry; two, because I thought she had pizzazz and could attract filmmakers; and, three, she wanted it so much. Her passion for the idea and her belief in the city and region - none of the other applicants came close."

The job was hers. The catch: She'd have to raise her own money. She gave herself 60 days. It took 64.

She forged partnerships with suburban counties, which ponied up support, and renamed her outfit the Greater Philadelphia Film Office. Economic-development grants came from state and regional groups. Balky unions were ready to negotiate.

In 1991, that limbo year, local movie production generated about $2.1 million. In 1993, the year after Pinkenson took over, reeling in The Age of Innocence and Philadelphia, it climbed to $21 million.

Since then, says Pinkenson, the office has brought in more than 300 films and series, with an estimated $300 billion in economic impact. It led the charge for state film tax credits, "the sharpest arrow in our quiver."

How did the office do it? People in the film trade describe Pinkenson as fluent in the language of business, a "one-woman LinkedIn." Legislators talk about her shrewd politicking. Directors say she thinks like a producer.

"My first impression of Sharon was that of a filmmaker," Philadelphia and Beloved director Jonathan Demme says. "Time after time, she found the most photogenic and cheapest solution to our problems."

Demme loves the city's versatility. Philadelphia used urban and suburban locations, while Beloved (1998) took advantage of 19th-century neighborhoods and rural scenery. "Then there's the magic of Philly itself," he says.

The office did not neglect homegrown talent, either. Director Louis Massiah praises its "generous assistance to local filmmakers." Mike Barnes, vice president of IATSE, the stagehands union, says, "Sharon works as hard to bring in a $500,000 movie as a $50 million movie."

Among the productions that got support: Cheryl Dunye's The Watermelon Woman (1996), Shyamalan's Wide Awake (1998), Terry Gilliam's 12 Monkeys (1995), Curtis Hanson's In Her Shoes (2005), and F. Gary Gray's Law Abiding Citizen (2009).

Pinkenson's flamboyant appearance, says Brown, "belies her steely and determined genius for luring movies here." Says Rendell: "Most pushy people alienate others. Not Sharon. Nobody doesn't like her."

The film office retrofitted as soundstages the old Civic Center, where Demme's Beloved and Shyamalan's The Sixth Sense and Unbreakable were made. Then the Navy Yard, where Shyamalan shot The Last Airbender - one of the eight movies he has directed in his hometown.

"There is a film industry in Philadelphia because of Sharon's efforts," Shyamalan says.

The film office fought for tax credits to attract production. During the state budget crisis in 2009-10, credits were slashed from $75 million to $42 million. They revert to $75 million in 2011-12.

Tax credits, says State Rep. Dwight Evans (D., Phila.), are "about jobs, jobs, jobs, from actors to caterers to special-effects artists."

Barnes says that during Pinkenson's tenure, permanent jobs for stagehands and electricians in the region rose from zero to 200. "It shouldn't be called tax credits," he says. "It should be called job stimulus."

A state audit in 2009 reported that film production accounted for 4,000 jobs in Southeastern Pennsylvania.

Sixty-five of them are at Shooters/DIVE, the postproduction company that moved to Philadelphia instead of New York in 2001 after a film-office charm offensive.

"When Shooters decided to branch out from advertising into film and television production, what got us started was a phone call from Sharon," president Ray Carballada says. "She told the production company of the TV show Hack that we could process dailies [raw footage]. A guy from L.A. came, saw we had the equipment, and 20 minutes later we had a signed contract."

Demme says that on The Silence of the Lambs (1991), "the help we got in Pittsburgh was top-quality. New York has an excellent film office. But in this business there's only one Michelangelo, and Sharon's it. Philadelphia is her canvas. Would she be as great in Topeka? Don't know."

Today, Pinkenson, 62, celebrates two milestones, the film office's birthday and the opening of the studio she lobbied for. "Philadelphia always had the locations and crew. We got the tax credits. We got the studio. Now we've got the whole enchilada."

Contact movie critic Carrie Rickey at 215-854-5402 or crickey@phillynews.com.