The youngster suffered a fractured skull and a brain haemorrhage at Michael Ayres' then home in Idle, Bradford, but despite his guilty plea to causing grievous bodily harm to the child, Recorder David Gordon was told that the boy's parents did not want him locked up.
Ayres, now of Lambert Place, Undercliffe, Bradford, eventually admitted recklessly shaking the boy in panic after he fell over with the baby as he carried him upstairs.
The child had banged his head, becoming unconscious, and barrister Andrew Dallas, for Ayres, said his client had instinctively and recklessly shaken the unresponsive baby.
"This was not the action of a wicked man or a violent man but the ill-judged panic of a normally gentle and loving person," said Mr Dallas.
Following the 2008 incident the baby suffered development difficulties, but the judge heard that he was now attending nursery, could say some words clearly and could make himself understood with gestures.
In a victim impact statement the boy's mother said she had given up her full-time job to help her son who she described as bright and very happy.
She said one of the reasons why they did not want Ayres to be locked up was the effect that would have on his own children.
Mr Dallas said Ayres, 35, who had no previous convictions, wanted to express his remorse and for not acknowledging what he had done earlier.
In deciding to suspend Ayres's 12-month sentence for two years Recorder Gordon said he had been particularly influenced by the "enlightened, civilised and forgiving attitude" of the boy's parents.
Ayres was also ordered to do 250 hours of unpaid work.