Rosado's son Christopher died of a drug overdose on May 11, 2012, two days before his first birthday. Rosado later admitted putting heroin and methadone in the baby's bottle.
Before being sentenced, Rosado read a statement in which he apologized for his son's death, saying it was a "tragic accident, nothing more, nothing less."
Assistant District Attorney Lorraine Donnelly urged McDermott to sentence Rosado to the maximum of 221/2 to 45 years in prison, saying Rosado thought "this was a way to calm a fussy child."
Defense attorney Bruce Wolf asked the judge for leniency, asserting that Rosado was a loving, doting father despite his own problems who " did something stupid and reckless."
Rosado and his girlfriend, Crystal Miller, 29, the mother of their two children, were both heroin addicts in rehab and taking methadone.
During the trial, Miller said that although she had been clean for six years on methadone, Rosado admitted to her that he had relapsed. On May 11, she said, she went to bed about 11 p.m., leaving Rosado watching television and the baby sleeping nearby in his bassinet.
She said Rosado told her he fed Christopher a bottle of formula about midnight and again at 3 a.m.
Miller said she was awakened at 6:30 a.m. by Rosado's cries of: "Call 911! Call 911!"
A partly filled bottle of formula on a table near the bassinet tested positive for heroin and methadone, a toxicologist said during the trial.
"I firmly believe you were putting methadone in his bottles on a regular basis to calm him down," the judge told Rosado.
Rosado said he wanted to "honor his son's memory with a life of sobriety."
McDermott told Rosado he would have time to do that in prison.
The baby, she said, was "the most vulnerable" of victims.
"He was incapable of anything but needing love," McDermott said.