Apart from Ali of course, which I think most would say was more exhaustion than having his bell rung. Has he ever said? I know he said Cooney hit him the hardest but George never really looked in trouble in that one but maybe that was because he could push Cooney away so easily. Because he's so lumbering, he does seem like the type of guy that once he goes down he's in real trouble but to my knowledge Lyle was the only guy to really knock him down.
In his bio By George Foreman says that two fighters rung the bell on him: Lyle and Cooney (after saying that it definitely was NOT either Ali or Young). After watching both fights, the Lyle knockdowns looked very devastating (Cooney may have hurt him in the first round, but did not knock him down). The referee was quoted afterward as saying he didn't think Foreman would get up from either KD from Lyle. Definitely Lyle.
He also stated that Ali never threw that last punch the probably WWOULD have 'rung his bell,' and for that, he was grateful to Ali.
First George was koed for a 10 count and the man who did that was Ali...against prime Foreman no less. Lyle of course came closest to doing the same. That last kd came from a devastating punch and George went down like he was shot. I do look back on his bout with Stewart as another bout where he could have been stopped. I was actually yelling at the ref to stop the fight as it looked like Georges face was coming apart with ever blow...many at ringside were doing the same. Blood spattering everywhere. Foreman was one tough determined fighter. He had the will to win of an all time great.
Young could not break an egg with his punches. He caught Foreman exhausted and off balance to get the flash KD.
Ive heard Foreman say that he could have gotten up from the Ali KD, but Ali had beat him mentally, George threw everything he had and Ali was still there. Nevertheless Ali KO aside, it would be Lyle. Go watch that fight if you haven't seen it. Lyle cracked Foreman at the end of round 1 and hurt him. If I was watching that fight live, I wouldn't think Foreman would get up after the KDs sheer will. Foreman Won by an inch. Cooney hurt him in round 1, wobbling big George. However George looked good in round 2, stepped up his aggression and brutalized Cooney. 40-0 Foreman, and peak comeback Foreman was extremely difficult to KO. You had to shake his will, the only man that could do that was ALI.
He just missed beating the count so of course if he could have summoned one additional second to get up he would have beaten the count....only to be put down for good in round 9.
Ali was the only man to ko George for a 10 count. great combination to do so...one of my fav all time ko combinations.
While I don't usually like to just pile on and agree with what everyone is saying, in this case I don't think there's a choice. The KD at the end of round 4 against Lyle is the closest I've seen to Foreman being genuinely out and with his wits scrambled. He got hit so sharp and went down so hard that I'm sure nobody seeing that live expected him to get up. I'm not sure exactly how he did get up, but he certainly was lucky there was no more time left in the round. Start at about 16:40 [yt]l8AVcEyyMco[/yt] Most honorable mentions would probably come from George's comeback. The main ones I've seen where he got his bell rung a bit were against Cooney and a journeyman/former Canadian heavyweight title holder Ken Lakusta. Foreman dominated Lakusta for a couple of rounds, then put him down in the 3rd. Lakusta decided to go out on his shield and as George walked in somewhat lazily, overconfident that he had the fight in control, Lakusta launched a big haymaker right that staggered Big George. George walked right into it and didn't see it coming. The two then slugged it out for about another 30 seconds before George put him down and out for good. Start around 9:28 [yt]E_1BuWtZIlk[/yt] I'm sure George has been hurt a few other times, like in the Alex Stewart fight where Stewart wrecked his eye, but I haven't seen it so I can't say if he got a proper bell ringing in addition to the more normal physical pain.