"At the heart of this case is a journalist doing her job," said Bryan Baynham, Robinson's lawyer.
Furlong's lawyer, John Hunter, however, said that his client had responded to an "attack."
Robinson is suing Furlong for statements made in response to a 2012 Georgia Straight article alleging he physically abused students as a teacher at a Catholic elementary school in Burns Lake, B.C., in the late '60s and early '70s.
In his opening statement, Baynham claimed Furlong defamed Robinson by attacking her professional abilities and journalistic standards, "because she reported on aspects of his past that he did his best to keep hidden."
Baynham said his client has suffered emotionally, physically and financially.
The small courtroom was packed for the start of a trial that will ultimately hear testimony from both plaintiff and defendant.
Robinson sat at the far end of one of three rows of seats, sunglasses perched on her forehead as she took notes. Furlong sat in a suit two rows behind, alongside the former head of communications for the 2010 Olympics.
The woman hearing the case, Justice Catherine Wedge, has her own Olympic connection: she competed as an equestrian in the 1976 Summer Games in Montreal.
Baynham detailed Robinson's qualifications as an author and journalist who has won acclaim for reporting on sexual assault cases connected with junior hockey. He said she has also extensively reported on aboriginal abuse.
Robinson's story began with a tip in 2009.
Baynham said Robinson started investigating the timeline of Furlong's arrival in Canada; his autobiography said he came in the mid-'70s, but records showed he was teaching at Immaculata Elementary School several years prior.
She travelled to Burns Lake, where she met a number of former students who signed affidavits saying Furlong had physically and verbally abused them.
Baynham said Robinson approached the Toronto Star and the CBC with the story, as well as the Georgia Straight, but the two larger news organizations backed away.
After the story ran in September 2012, Furlong held a news conference in which he said Robinson was on a "personal vendetta."
He also filed a defamation case, but Baynham claimed Furlong did nothing to advance it.
Furlong discontinued the suit after three civil suits against him were either dismissed or withdrawn.
"Mr. Furlong wanted his claim for defamation tried in the media or the court of public opinion," Baynham said.
"His legal right to clear his name died when he filed that notice of discontinuance."
Response to attack
Baynham claimed Robinson spent $150,000 fighting Furlong's claim and has ended up in hospital emergency rooms several times because of stress. He said she has a hard time finding publishers for her work.
But Furlong's lawyer, Hunter, insisted outside court that his client was entitled to react to Robinson's story.
"Response to attack is sort of the catch-word," said Hunter.
"I don't know how there could be very much doubt he was attacked."
The only witness to testify was journalism expert John Miller, a former Ryerson professor and Toronto Star editor.
He testified about the pitfalls of investigative reporting and said it's a slur to call a journalist an activist.
Under cross-examination, he was asked about a recent journalistic scandal at Rolling Stone magazine concerning a false allegation of sexual assault.
He agreed reporters should try to disprove theories as well as prove them.