Dennis Carl Smith, 40, pleaded guilty Monday morning to three counts of Reckless Homicide and was sentenced to 10 years in prison.
Judge Paul Burch gave Smith credit for the 227 days he spent in jail before getting out on bond to await trial.
Smith admitted to being drunk in 2009 when his car slammed into the back of another vehicle on Highway 15 Bypass about two miles from Hartsville.
Ruby Brown, 60, and her two grandsons, Artivas Gilbert Brown, 17, and Antonio McFadden, 19, died as a result of the crash.
Smith apologized to the victims' families.
"I am sorry for your loss. If I could take it back or do anything different, I would. I'm so, so very sorry," said Smith.
Brown's husband says he's glad Smith has been sentenced.
He says dealing with the loss of his wife and grandsons has taken a toll on his family during the past four years.
"A lot of stress and what not. Family went through a whole lot. Still going through a whole lot because she was a very good wife and a very good mother and friends of a whole lot of people," said Wilk Brown.
The victims' families have sued Smith and two Hartsville bars they say he visited the night of the crash.
Smith has to serve at least 85% of his sentence before he's eligible for parole.