Crawford was the heavy favourite going into the bout, but there was still a belief that Porter could draw him into a war.
Showtime himself is a two-time welterweight world champion, but he was stopped for the first time in his career after a brutal performance from Bud.
The pair traded counters in the second round and brawled briefly, setting the Las Vegas crowd alight.
The third round was more cautious from both, but Porter picked up a cut over his right eye due to a clash of heads before going down, which the referee adjudged to have been a slip.
Crawford switched stances in the fourth round, and he began to assert his dominance using his left hand. He himself then picked up damage to his eyes in the sixth, after the pair accidentally clashed heads again.
The champion won the ninth round against a tiring Porter.
Porter went down early in the 10th after Crawford caught him with a left uppercut. Porter managed to get up, beating the count easily, but just moments later, Crawford dropped him again with an electrifying combination, culminating with a right hook.
Porter fell to the canvas, causing his father and trainer Kenny Porter to climb up to the ring apron and withdraw his son from the battle.
Porter was visibly annoyed at himself, as he struck the apron with his fist as he lay on the canvas. In contrast, Crawford jumped up and down in front of the sold-out arena.
The victory means that Crawford remains undefeated from his 38 fights, with 29 knockouts. He was also leading the official scorecard at the time of the TKO with two scores of 86-85 and one of 87-84.
Crawford will now set his sights on a fight with the also undefeated Errol Spence Jr.
Porter, meanwhile, aged 34, announced his retirement from the sport in his post-fight press conference. He retires with a record of 31-4-1, and 17 knockouts.