Sir Ron Lionheart sounds like the textbook example of this in his videos. He's so infectiously enthusiastic, you can't not smile while listening to him. Just read the comments on his videos.
There are an unusual number of US politicians with this reputation, possibly because the US has this reputation in general (Eagleland, Mixed Flavor). As Cracked put it, the Europeans treat the US as the guy they get drunk with and say, "This guy! He might be a bit crazy, but you know, he's all right."
Not to be outdone is Texas' own Lyndon B Johnson. His 'Treatment' is legendary for its burly method and its high success rate.
Interestingly, Liu Bang, who founded the Han Dynasty of China was one of these, although Zhang Fei is more often remembered to be one.
King Henry VIII (the one with the six wives) was said to be one of these. To his friends, at least. To his enemies or to anyone whom he suspected of betraying him, he could be a total murderous bastard. Henry's Boisterous Bruiser aspect often gets played up in portrayals of him, notably the version of him played by Charles Laughton in The Private Life of Henry VIII.
Another English king, Charles II, also fits the trope: called the "Merry Monarch," Charles brought back color and, shall we say, joie de vivre back to England after years of stern Puritan rule. He loved a good joke (he's one of Britain's snarkier monarchs) and a good drink, had an obscene number of mistresses, and was often rumored to have liaisons with men, as well (though he still had a soft spot for his wife Queen Catherine, standing by her side when she came under fire and when she became an Ill Girl). He also enjoyed the theater (something else the Puritans had banned), and the Restoration Comedy dates from the first decade or so of his reign.
Charlemagne was a giant by any standard of his day, a renowned warrior as much as a ruler, and oh yeah, he was so informal that when he wasn't holding court with more or less anyone willing to drink and eat with him, he was insisting they join him while he bathed so the festivities wouldn't be unduly interrupted. He was the least formal king ever.
Oliver Reed. He had a reputation for his whole career as a hard-drinking hell-raiser who bore scars on his face from a bar fight in 1962. He died of a heart attack at age 61, after a night of hard drinking in which he consumed 3 bottles of rum and beat 5 sailors at arm wrestling.
George Washington was this but as an avid social climber and aspiring gentleman, he worked hard to suppress his bruiser qualities.
Vikings. A favorite pastime during feasts was inventing short poems which either told about one's own accomplishments or insulted another as subtly and cleverly as possible. The proper way to answer such an insult was to counter it with a poem of your own. Someone pulling out a sword during such friendly banter was considered nothing but a brute, and as such not a proper viking.
Ernie "Turtleman" Brown Jr., as shown on the Animal Planet documentary show Call Of The Wildman. A friendly, outgoing and highly energetic man known for his signature rebel yell and catching anything from snapping turtles to coyotes with his bare hands.