David Palmer in 24 is an example of this trope. He acts that way at times and he's not particularly vicious.
Mack on Agents of S.H.I.E.L.D. is 6'4" and carrying a lot of muscle, but very kind (albeit with a penchant for Brutal Honesty) and actually kind of nerdy, as well as one of the few characters with the patience to help Fitz work through his post-brain injury communication problems.
Ray Palmer. He's tall and muscular, but one of the most genuinely nice characters in the show. Subverted in that no one actually seems frightened of or intimidated by him.
The same goes for Diggle, who is The Big Guy and The Lancer of Team Arrow, but is also the guy who keeps Oliver from going too far and is a very loving father.
Mr. T's character B.A. on The A-Team has a Gentle Giant side, in which his fear of flying forces the others to drug him whenever they need to get him on a plane. He is also revealed as a Genius Bruiser in episodes that feature his skills as an electronics and gadgetry whiz. He also shows the gentle side in any episode dealing with kids. Of course, this is also true of the actor in real life, so it fits. (As well as in his cartoon show.)
Olag Gan from Blake's 7, who is also a Technical Pacifist due to having his brain altered by the Federation.
Hoss Cartwright from Bonanza fits the trope; a truly strong fellow whose love for children and all round sweet nature are always in evidence, in addition, he is quite naïve. However, any bully pushing around an innocent around him is going to regret it most forcefully.
Frankie from Boy Meets World is ultimately revealed to be one when he has a good influence.
Sgt Terry Jeffords on Brooklyn Nine-Nine played by ex-football player Terry Crews. A co-worker describes him as an "enormous, muscular Ellen Degeneres".
Jaime Palillo. Big, strong, loud, gluttonous — but friendly towards everyone, laid back, always in a good mood, and never tolerant of any bullshit against his friends.
Its In the Blood, actually: his parents are seen on-screen, and both Mr. and Mrs. Palillo are just as large and kindhearted as their son.
Profesor Jirafales in El Chavo del ocho, the taller of all the actor (as Rubén Aguirre, the actor who played him was almost 2 meters tall), yet he's a very committed and caring school teacher and frequently the moral voice on the show, he opposes violence and hitting children as Don Ramón often does. Of course, he more than once beats Don Ramón, especially when he thinks Don Ramón is promoting boxing among the children, which according to him is encouraging violence.
Coach: Dauber is so sweet, he has trouble getting the players (most of whom are very big themselves) to see him as an authority figure.
In the second season of Cobra Kai, this would become Chris' defining characteristic: huge, peaceful (if a bit on the slow side), and immediately at home in Miyagi-do Karate after a taste of Cobra Kai training. But he could still lay the smackdown, as Mitch found out the painful way.
The massive Detective Vera fits this trope. Despite being snarky, he's amazingly good with children and as Rush tells a rape victim: "He only looks like a Neanderthal."
Detective Jeffries is even bigger than Vera and even more calm (usually).
Subverted in Metamorphosis. The Circus Giant everybody thought was mentally handicapped and a gentle soul, was actually highly intelligent and a cold-blooded murderer.
Nick Stokes. Evident when Greg Sanders is attacked in the episode "Fannysmackin'"; normally a gentle soul, Nick went berserk at the kids who were taunting him. For a few seasons, some fans joked that the constantly tormented Nick would have his "Day of Justice."
Grissom himself is almost never angry. However, if you make him really angry, like by selling drugs to kids, Grissom may lose his cool and go into quite the rage.
Archie "Snake" Simpson from Degrassi. Minus the "not book smart" part in this case (one of the smart kids in the '80s version, he comes back as a teacher and makes principal well before age 40).
In Dracula (2020), the Demeter's cook is a hulking bearded brute of a man with a heavy metal spike in place of his left hand, but underneath his intimidating appearance and anti-Romanian racism he's actually a pretty swell guy.
Who could forget The Big Guy Robert from Everybody Loves Raymond? He's massive, hulking, sometimes seen as dull-witted but actually very smart in many situations, became a cop, and is one of the gentlest guys you will ever meet, both in the show and reality.
D'Argo of Farscape. Though he was primarily a Warrior Poet, he tended to be very much a gentle giant around children — his friendship with Cyntrina in "DifferentDestinations" being the most obvious example.
The Friendly Giant from the Canadian children's show of the same name.
Game of Thrones: Hodor, the gigantic, simple-minded servant who is scared of thunder and unable to defend himself unless he is controlled by Bran. This was probably the reason he was chosen to carry Bran around. Also, despite finding himself in increasingly dangerous circumstances, he continually refuses to hurt anyone, and was extremely reluctant to take one of Sam's dragonglass knives and only did so on Bran's insistence. In "Oathkeeper", he can't bring himself to fight back against the Night's Watch mutineers. In "The First of his Name", he is utterly horrified after being forced via warging to kill Locke. In "The Children", he can't bring himself to fight back against wights. However, in "Home", it is shown that back when he was Wylis, he was eager to train and spar with the other children, but Old Nan scolded him and told him not to participate in foolishness.
There is a reason Finn from Glee has been called Frankenteen.
David Karofsky, after experiencing a change of heart, is also shown to be sensitive and gentle on the inside. Aw.
Monroe on Grimm; played by the very tall Silas Wier Mitchell. Clockmaker, cellist, gourmet vegan chef, geeks out in decorating for both Hallowe'en and Christmas, beloved by the children of the neighborhood (except for the bullies). Also is a retired werewolf.
The Cyclops in the episode with An Aesop is that people should not be judged by their looks, the Cyclops is a monstrous giant, but is a nice guy.
Hercules befriends the giant Typhon, who is so nice that his mere presence makes his wife and children (all of whom are monsters) lose any inclination towards evil.
Marshall from How I Met Your Mother. He's played by 6'4" Jason Segel, but he's the most sentimental (and sympathetic) character on the show, but winds up coming in handy when Ted and Barney try to pick a fight outside the bar. He takes after his father in this regard.
Eliot Spencer on Leverage. He's not big heightwise but he's solid muscle and a powerful fighter, which is what makes him such an effective "hitter" for the merry band of do-gooding criminals. "Mushy" attributes include a love of cooking (he's a Master Chef), a fondness for children, and proclaiming his favorite movie is Casablanca.
The Lord of the Rings: The Rings of Power: The Stranger is this to the little Harfoots. They even call him "the giant". He has tremendous powers that he cannot control yet and is always worried he may accidentally hurt them, and when that finally happens, he choses to leave them for their own safety.
The overweight lovable slob Hurley from Lost fits this to a T — he's also quite resourceful. He made a golf course on the island early on.
Willy on Mission: Impossible mostly fits, although it can be assumed he was just as intelligent as the others.
Herman Munster of The Munsters, definitely. Body of Frankenstein's Monster, personality of a Bumbling Dad.
Really, most anyone played by Fred Gwynne qualifies. His 6'5" frame, baritone voice, and pleasant, shy nature made him a natural for these parts.
Night Court's Bull Shannon. He's a 6'8", bald, muscular, very intimidating guy who's strong enough to crush a bowling ball in his bare hands (seriously, he did just that in one episode), and he's one of the nicest guys you'd ever meet, so nice that more than one young mother has hired him to babysit their children.
Nurse Jackie has this in the form of Thor, a tall, imposing dude who is sweet as sugar, cute as a button, and gay as a glittery top hat. Calling out "Thor!" in an early episode brings him looming, scaring off the creep, and when Jackie says "Thank you," he spins around with a perky "No problem!"
Matt from Operation Repo (minus the the "don't push him" part). The guy is a big bald dude with tree-trunk arm who runs and hides at the first sign of trouble. At one point he began crying after being shot with pepper spray (actually crying, as in "boo-hoo".)
Kubiak from Parker Lewis Can't Lose, although he starts as a bully. Abraham Benrubi, the actor for Larry "Kube" Kubiak often plays this role, and is noted in the Real Life section for also being this.
Dagwood from SeaQuest DSV/2032 was a failed prototype of a brand of genetically engineered soldiers. Not only was his intelligence lower than his creators expected, he was so gentle that when the rest of the crew had their aggression heightened, he remained the same because there was "not a mean bone" in him.
Teal'c from Stargate SG-1: former First Prime of Apophis, crack shot with a staff weapon or a machine gun, stronger than dirt. At the end of one episode, he gives a little girl a honkin' huge water gun, then pulls out one of his own. Much hilarity ensues.
The giant at the beginning of the Season 2 of Twin Peaks. He's a lot more mild-mannered than most of the other residents of the Black Lodge, and is implied to be some kind of Big Good as well given the helpful advice he gives Agent Cooper.
Ultra Series: The Ultramen, who are 40-60 meter tall alien giants composed of light and have dedicated themselves to protecting humanity and the universe from kaiju and evil aliens. Occasionally, some of the kaiju can be this as well, which in that case, the Ultras and defense team will usually have to assist them somehow.
The Wheel of Time (2021): Loial is an Ogier, a towering humanoid man who inspired fear from both Rand and people earlier in Tar Valon, to the point a mob chased him around the city. However, in truth he's harmless. Loial is a highly polite, scholarly fellow who has no ill intent toward them.
Conrad from Wild Boys. The biggest of the bushrangers, he is the only one who isn't an outlaw at heart; having being forced to give up an honest trade (farrier) and turn criminal when he was framed for a crime he did not commit.
Goliath in Xena: Warrior Princess is a gentle, good-hearted family man forced to fight David.
