The 40-year-old man, who denied manshlaughter and robbery, was said to push the elderly woman to the ground and grab her handbag as he fled the scene.
His victim was left suffering multiple injuries, which included a fractured neck and cheekbone. Less than two weeks later Kaczan died from pneumonia, brought on by her injuries.
Lynsey O'Donnell from the Crown Prosecution Service said:
"The evidence in this case created a jigsaw that, when pieced together, showed no-one else could have carried out the attack. We presented CCTV and mobile phone evidence to prove he was there at the time of the attack, evidence that he had stopped and got out of his car and that his behaviour afterwards showed he was hiding something more serious than finding and taking a handbag.
"The saddest aspect of this case is that an otherwise healthy lady has lost her life so that this man could satisfy his selfish desire for easy money. Mrs Kaczan was well known and well thought of within her community and all those who knew her are devastated by her tragic death."
The court heard the defendant claim that he stopped his car when he saw a handbag on the ground, picked it up and drove off with it.
"I didn't rob no-one and I didn't see her — if I did see her I would probably ask, 'Miss, is that your bag?'" he said.
The Polish-born Derby resident admitted that he had a substance abuse problem since the age of 18 and was actually visiting his dealer at the time of the incident to purchase £20 worth of heroin.
"When you were arrested, you had £100, was that the remainder of the money stolen from Mrs Kaczan?" the prosecution asked Waszkiewicz.
"No that was my money," he responded.
Derby Crown Court heard Waszkiewicz's case and issued the conviction.