O'Brien, who built a practice around a reputation as a churchgoing family man, told the victims: "I don't want you to be insulted by my apology. I'm truly sorry."
Turning toward the judge, he said, "It doesn't change the fact, your honor, I did wrong . . . Maybe [the victims] can do a better job of forgiving me than I can forgive myself."
Superior Court Judge Linda G. Baxter told the former lawyer he had victimized "especially vulnerable people."
"In many ways, Mr. O'Brien, you are a predator," she said.
"You used as your weapons bank deposit slips, bank withdrawal slips, pencil and paper. You took advantage of your position of trust . . . and preyed on elderly people, grieving people, developmentally disabled people."
O'Brien pleaded guilty last August to two counts of theft. One accused him of stealing about $850,000 from the estate of Stanley Mich, who had left the money for the care of his autistic son.
The son, Ronnie Mich, now 62, had been used to a life of familiar surroundings but was forced to sell his Audubon house and move into an adult group home for the disabled.
The second count against O'Brien consolidated the thefts of the other 38 victims.
O'Brien also pleaded guilty last August to violating probation on a 1999 conviction of misappropriating money entrusted to him. He was ordered then to forfeit his law license and to pay $269,000 in restitution.
Yesterday, he was sentenced to four years in prison on that violation, to be completed concurrently with the 18 years.
O'Brien's attorney, Robert Agre, said his client was "shocked by the length" of the sentence "but almost numb by everything he heard in the courtroom."
Assistant Camden County Prosecutor Mark Chase called the judge's decision "fair and appropriate." And Camden County Prosecutor Vincent Sarubbi said the case, with its use of a court-appointed special master to recover money and a receiver to distribute the funds to compensate victims, would set a precedent for the handling of similar white-collar crimes.
During yesterday's hearing, several victims described how O'Brien used his position as guardian of their estates or investment counselor to rob them.
Some laughed when Agre offered O'Brien's apologies.
George Stone, 59, a former neighbor and friend of Ronnie Mich's who helped him transition to the group home, said O'Brien had hurt many people; "it can't be measured."
He asked Baxter to sentence O'Brien to "one year for every victim. That would be good. It would put him away for good."
Ronnie Mich's aunt, Sister Theresa Mich, a nun at St. Francis Convent in South Philadelphia, hugged Stone and thanked him for being the family spokesman.
Her sister, Sister Rita Mary Mich, who also resides at the convent, wept as the judge then returned photos of the Mich family in happier days, before Ronnie had been forced from his Audubon home.
"I want people to know what the family suffered," Sister Theresa said in an interview. "How can anyone destroy the life of an adult who is autistic?"
Patricia Fore Logan, 53, of Mount Ephraim, called on Baxter to impose a long prison term without parole. She said she and her mother, the late Edith Fore, lost at least $200,000 to O'Brien.
Fore, who died at age 81 in 1997, was known for her role in a TV commercial where she uttered the line, "I've fallen and I can't get up."
"He took our lives," Logan said. "Dennis O'Brien treated us like objects."
Logan, who cared for her infirm mother, said O'Brien wrote Fore's will, had power of attorney, and put Fore's house and money into a trust. At one point, she said, he borrowed $100,000, which was never returned.
"He didn't even put a tombstone on my mother's grave," she said. "My mother died a cold and lonely death and lies in an unmarked grave."
Irene DiRenza of Westmont, who lost $107,000 to the former lawyer, told O'Brien: "Dennis, you are indeed a Dr. Jekyll and Mr. Hyde personality. I'm broke."
O'Brien sat silently, his head bowed as the victims spoke. When they finished, he described how the thefts had occurred.
"I began to spin out of control . . . when a couple of projects began to fail," he said.
"That's when I really got into the sin of pride, thought I could out-work the situation."
He said he now realized the impact of his crime. "I awake with it every day. The awareness of that impact is crushing me. . . . The weight is burying me."
Contact staff writer Edward Colimore at 856-779-3833 or email@example.com.
For previous coverage of the Dennis O'Brien case, go to: http://go.philly.com/ronniemich