Dinesh Kumar shows a picture of his son Gaurov to the media outside an Appeal Court in Toronto on Thursday after being acquitted of causing the death of his infant son in 1992. (Chris Young/Canadian Press)

A Toronto man who was convicted in the death of his infant son 19 years ago based on the testimony of discredited pathologist Dr. Charles Smith has been acquitted.

On Thursday, the Ontario Court of Appeal threw out Dinesh Kumar's conviction, calling it unreasonable.

The Crown and defence had made a joint request to have the conviction overturned. But while the Crown agreed Kumar's conviction shouldn't stand, it pointed out his guilty plea was valid at the time and based on current medical knowledge.

Kumar told reporters outside the Toronto courthouse he was "very happy" with the ruling.

"I'm going to get that letter and I'm going to put it in my community temples so at least those people — they know that I'm not a killer. I'm an innocent guy," he said as he wiped away tears.

Kumar pleaded guilty to criminal negligence causing death in 1992 and was sentenced to 90 days to be served on weekends.

The lawyer for Kumar says his client was under a "multitude of pressures" when he made the plea.

Discredited pathologist Dr. Charles Smith, shown above, testified in 1992 that Dinesh Kumar's five-week-old son died of shaken baby syndrome. (Canadian Press)

Among those pressures was the expert opinion of Smith, who testified Kumar's son, five-week old Gaurov, died of shaken baby syndrome. The Court of Appeal, however, was recently presented with new information from medical experts who found Smith's conclusion in that case was no longer scientifically valid.

A 2008 inquiry into Smith's work found that between 1991 to 2001, there were 20 instances where he made mistakes leading to dubious conclusions of criminal wrongdoing. Thirteen of those cases resulted in convictions.

The inquiry, led by Stephen Goudge, found he "actively misled" his superiors, "made false and misleading statements" in court and exaggerated his expertise in trials.

With files from The Canadian Press