Wood's corner retired their man at the end of the sixth round, by which time their game-but-outclassed fighter had been down three times.
Geale took away Wood's WBA Pan African middleweight title and won the vacant IBF Pan Pacific belt in their fight at Sydney's Hordern Pavilion.
For all the pre-fight talk about Wood's perceived penchant for rough tactics, it was Geale who was the only man penalised by referee Charlie Lucas.
He was deducted a point after the second of two low blows about a minute apart in the second round.
While Wood was cautioned for punching after the break and punching to the back of the head, he was unable to disturb Geale, who in the fourth round shoved his opponent to the floor. Geale controlled the fight with his speed, skill and accurate punching.
Geale (30-2, 16 KOs) dropped Wood (12-4-1, eight KOs) in the first and again late in the fifth, after the underdog was having one of his better spells.
He finished the round all over Wood, but the bell saved him.
It was a similar situation again in the sixth, as Wood was again dropped late in the round and finished it by sliding across the ring into the ropes.
His corner called the fight off a few seconds later.
Earlier, rugby league star Paul Gallen made an exhilarating professional boxing debut, climbing off the canvas to stop Herman Ene-Purcell in two frantic rounds.
The NSW and Cronulla Sharks captain was dropped by a left in the first round, but showed great heart, and determination to storm over the top of his opponent in the second.
Geale was leading 59-52 on two of the judges' cards and 60-51 on the other at the time the fight was halted.
"I wanted to come out and be dominant, and show him what it was going to be like," Geale told AAP.
"I wasn't really surprised that I was able to hurt him, but I was a little bit surprised with the consistency I was able to hurt him with."
Asked about the fight with Golovkin he craves, Geale said "that would be great, that would be exactly what I want".
"My team will go back and see if we can work out a date."
Wood had no complaints about the result and congratulated Geale.
Despite the bad blood and angry words exchanged by the fighters in the lead-up to the bout they shook hands after the contest.
New Zealand's Robert Berridge (23-1-1, 19 KOs) retained the Pan Asian Boxing Association light heavyweight with a tenth round stoppage of Australian Kerry Foley (14-2-1, 12 KOs).