He's not 6-foot-5. He's not 23. He doesn't wear No. 7. And he doesn't have a goatee. In fact, Brian Jackson doesn't resemble Steelers quarterback Ben Roethlisberger in any way.

But that didn't stop the car salesman from duping a woman into believing he was Big Ben in order to go out with her, authorities said.

Now Jackson has a date of a different kind -- in court.

Detectives from the Allegheny County district attorney's office yesterday accused Jackson of harassing a woman named Mary Groft, who broke off contact with him this month after seeing through his alleged deception.

It wasn't the first time Jackson used the black-and-gold to facilitate his love life, authorities said.

In September, he reached deeper into the Steelers depth chart and impersonated fourth-string quarterback Brian St. Pierre to woo a woman named Julie Valo, the affidavit said.

After a few weeks, Valo figured out Jackson's ruse and told him she wanted nothing to do with him, the affidavit said. He harassed her, however, by following her and surprising her at various places, according to the affidavit.

The investigation isn't over.

"We believe there are other victims out there," Mike Manko, spokesman for the district attorney's office, said yesterday.

A handcuffed and shackled Jackson appeared at noon before District Judge Oscar Petite Jr. to be arraigned on criminal mischief and two counts of harassment.

Accompanied by his attorney, Paul Boas, Jackson, 31, respectfully answered questions. He said he was a car salesman from Baldwin Borough who lives with his fiance. Authorities, however, supplied a home address of Abel Avenue in Brentwood.

Petite released Jackson on his own recognizance and ordered him to be evaluated at the jail's behavior clinic before his July 25 preliminary hearing.

Boas declined comment and hustled his client from the Pittsburgh Municipal Courts building.

Roethlisberger's agent, Leigh Steinberg, however, was happy to speak, having been the victim himself of an impersonator. The movie character Jerry Maguire was loosely based on Steinberg, and someone once tried to pass himself off as the sports agent at a Las Vegas casino to secure credit.

"These are the unfortunate difficulties inherent in celebrity. People need to be careful, to ascertain the validity of claims that anyone makes who purports to be a celebrity," Steinberg said yesterday.

"Fortunately for an athlete as prominent and ubiquitous and identifiable as Ben, it's not normally a difficulty."

True. But St. Pierre might be a different story. Standing behind Roethlisberger, Tommy Maddox and Charlie Batch in the quarterback line of succession, St. Pierre has hardly been in the limelight.

In September, the affidavit said, Valo met Jackson on the South Side, where the suspect told her he was St. Pierre. The two exchanged phone numbers, and they were in touch for two to three weeks, the affidavit said.

Valo told investigators that the ersatz quarterback would sign footballs for neighborhood kids and autographs for anyone who asked. The ruse was so deep that Jackson would discuss his "teammates," talk about Steelers information and tell Valo when he was going out of town, the affidavit said.

He even told her to watch a game.

That was Jackson's undoing.

Valo turned on the Steelers one day and saw Brian St. Pierre on screen. Despite sharing a first name, Brian Jackson was no Brian St. Pierre.

After the game, the affidavit said, Jackson called Valo and she confronted him. He told her she was "crazy," according to the affidavit, and said he looks different on TV.

Valo didn't buy it, and told Jackson they were through. She told him not to contact her again, but he persisted, according to authorities. A man pretending to be Roethlisberger -- investigators believe it was Jackson -- called her, as did a woman posing as Big Ben's girlfriend.

Valo told authorities that Jackson called her as recently as July 7.

In June, authorities said, Jackson adopted Roethlisberger's identity. He approached Groft in a pizza shop on Brookline Boulevard wearing sunglasses and a baseball cap, according to investigators.

Jackson told Groft that he was a friend of Roethlisberger and that she was Big Ben's type. They exchanged phone numbers, and then Groft and the faux Roethlisberger spoke for several weeks until they set up a date.

Jackson showed up at Groft's house July 6, when he presented her with an autographed football, posed with neighbor Larry West for a picture, and then signed West's football jersey, the affidavit said.

Authorities charged Jackson with criminal mischief for ruining the $75 jersey with a fake autograph.

When Groft got home from her date, West showed her a newspaper article about Roethlisberger. She called Jackson's bluff and told him not to contact her anymore, but he continued to call her, the affidavit said.

The investigation was initiated by the National Football League's security representative in Pittsburgh, Mark Ninehouser, a former Pittsburgh police sergeant, and turned over to detectives Frances Laquatra and Randall Ricciuti of the district attorney's office.

First Published: July 16, 2005, 4:00 a.m.