The 48-year-old boxer claimed a unanimous decision against Tavoris Cloud, winning 116-112, 116-112, and 117-111 on the judges' cards at Brooklyn's Barclays Center on Saturday night to eclipse his 2011 WBC light heavyweight title victory over Jean Pascal at the age of 46.
"(Trainer) Naazim (Richardson) told me what to do, I stuck to the gameplan, it was trying to throw combination punches, and throw them often," Hopkins said after improving his record to 53-6-2 (32 KOs).
Age has shorn him of his power but Hopkins proved he remained a master technician as "The Executioner" claimed a satisfying victory over a boxer from the stable of his former promoter Don King.
Hopkins opened a cut on Cloud's left eye in round six with a short left hook even though referee Earl Brown ruled it to be from an accidental headbutt.
Cloud, who subsequently complained of an elbow problem, sustained a cut on his right eyelid as well in the 12th round from a clash of heads.
"I have a history of destroying young champions and then we don't see them again. Not sure if you'll see Cloud again," Hopkins said after handing his opponent a first loss in 25 bouts.
"I wanted to show the forty-and-up club still rules," the Philadelphia-born fighter added.
Hopkins made his professional debut in 1988, the start of an illustrious career which included a decade-long reign as the world middleweight champion.
(Reporting by Amlan Chakraborty in New Delhi, editing by Patrick Johnston)