As the (self appointed) head of ranch security, Hank has a very important job to do...as he keeps telling himself.
- Animal Jingoism: He relishes the animosity that dogs and cats have with each other.
- Betty and Veronica: Hanknote is the Veronica to Platonote 's Betty. Beulah, the Archie, consistently chooses Plato, although there are hints she'd like to choose Hank.
- Bullying a Dragon: He does this to the titular rottweiler in The Case Of The Raging Rottweiler by making fun of him and even waving his butt in front of him, much to Drover's dismay and the rottweiler's outrage. Drover even points out how bad an idea this is in the ensuing song "It's Not Smart to Show Your Hiney to a Bear."
- Casanova Wannabe: He often tries to get the attention of many a female canine, but usually comes up short due to his actions or attitude. The only one who constantly shows herself to be interested would be Missy Coyote, but unfortunately for the two of them Hank kinda pissed off the rest of the coyote tribe.
- Catchphrase: He'll usually say "It's me again, Hank the cowdog" at the start of every book, and he'll usually say "Case closed" at the end of every book. Sometimes, he'll even say "By George."
- Cool Uncle: To his nieces and nephews in the town. His sister, on the other hand, thinks that he's a bad influence to them.
- Friend to All Children: He promises to protect children against "all manner of monsters and evil things". He's protective of Loper and Sally May's son Alfred, and he eventually gets protective to a litter of kittens even if he hated cats.
- Genius Ditz: Despite not being very bright, he still understands a lot about ranching, and knows some ideas the cowboys use that don't work.
- Heroic Dog: He has sworn an oath "to protect and defend all innocent children against all manner of monsters and evil things." Even though he's quite often Lord Error-Prone, he's always on call when someone's in real trouble.
- Interspecies Romance: One of his many crushes is Missy Coyote. She seems to be the only girl that reciprocates. Also has a one-sided crush on Ms. Viola, a human.
- Jerk with a Heart of Gold: He may be a braggart and full of himself at times, but when trouble comes, he'll live up to his bragging and save the day.
- Large Ham: He loves showing off his supposedly amazing charm, bravery, and intellect whenever he gets the chance.
- Lord Error-Prone: He faces imaginary threats almost as often as he faces legitimate ones. There's even a sequence where he and his sidekick, Drover, confuse a thunderstorm with an enemy invasion. Of course the fact that he has gone toe-to-toe with actually dangerous enemies gives him a little more credit than most.
- Mailman vs. Dog: He sums it up in his own way:
Hank: Why do we bark at the mailman? Because by George, we cowdogs have always barked at mailmen, and we always will!
- Narrator: Every story in the series is told by Hank himself.
- Papa Wolf: One of the things that's likely to bring out Hank's heroic side is children being threatened. In Faded Love, he attacks a rattlesnake (despite being terrified of it) to protect Little Alfred, and in The One-Eyed Killer Stud Horse, he attacks the titular horse to protect the little girls it was going after.
- Why Did It Have to Be Snakes?: Hank is terrified of snakes.
The assistant head of ranch security, Hank's constant companion and frequent sounding board, Drover is proof that when the going gets tough, the tough get going... right back to the tractor shed until the scary things stop happening.
- A Day in the Limelight: Drover gets his own backstory and POV in "Drover's Secret Life".
- Cowardly Lion: In The Case of the Prowling Bear, he runs back to protect Slim from a black bear even before Hank and while he doesn't bite it like Hank does, he does stand his ground and bark.
- Cowardly Sidekick: A Running Gag is that Drover hates anything that contains so much as a hint of danger.
- Lame Excuse: Whenever Drover suspects the slightest possible risk, he'll complain about his leg hurting.
- Lovable Coward: He hates anything that sounds scary or dangerous, and will frequently try to beg out of it by groaning about his leg or simply running away before Hank can stop him. However, he's still a sympathetic character, and on rare occasions, he has been known to do some brave things.
- Obfuscating Stupidity: Drover isn't the sharpest tool in the shed, but he's not not nearly as dumb as Hank thinks he is, especially when it comes to his own safety.
- Too Dumb to Fool: often when Hank is smart enough to fool himself.
Pete the Barncat
Sally May's pet cat and Hank's Arch Enemy
High Loper's wife who gets easily annoyed by Hank.
- Kind Hearted Cat Lover: Played with. She's a good woman and very fond of Pete, but given that Pete is an antagonist, her favor for him is portrayed as misguided.
- Mama Bear: Mother of Little Alfred and Baby Molly. Unfortunately, Hank is quite often the target of her scorn for "corrupting" her children. Still, more than once she's stood up to some pretty serious dangers to keep her kids safe.
- Throw the Dog a Bone: When Hank does something great (even if she's not sure it was intentional) she'll reward hank with love...or bacon.
A bachelor cowboy who serves as the hired hand.
- Deadpan Snarker: Has his moments
Slim: If a man could get into a dog's mind, he could sure write a book...or get locked up in the insane asylum.
- Dreadful Musician: At least according to Hank and Drover, as they find his songs insulting.
- Hypocritical Humor: Calls Hank and Drover dumb, when he's no genius himself.
- Lethal Chef: Just listen to his song, "Maters and Taters".
- Meaningful Name: His bonehead ideas usually don't work.
- Men Can't Keep House: He really only cleans it when Viola is coming over...and even then it usually doesn't work.
- Oblivious to Love: Did not understand for a while that Ms. Viola is in love with him...for whatever reason. Even Hank knows she likes him. He eventually does propose to her though.
- Trademark Favorite Food: Always seems to have some Beef Jerky on hand. Also loves his Mackerel Sandwiches.
High Loper and Sally May's son.
- Adorably Precocious Child: Sees his dad as a role-model.
- Character Development: When the books started, he would sometimes abuse Hank and Pete for his own entertainment. He still gets into trouble but is more good natured and even helped the cowboys during a roundup in a drought.
- At the start of the books, he could talk to animals due to his young age. He eventually grew out of it. He's still good friends with Hank, though.
- Interspecies Friendship: Back when he could talk to animals.
- Platonic Declaration of Love: After Hank gets into the garbage can in "The Garbage Monster From Outer Space" and Sally May threatens to take him to the pound, Little Alfred begs his mom not to take Hank away because Hank is his friend and he loves him. Because of this, Sally May relents and then warns Hank not to get into any more trouble.
Wallace and Junior
A father and son pair of buzzards.
A local woman who lives with her dad on a ranch. She is romantically attracted to Slim Chance, and shows up occasionally in parts of the series that involve him.
Eddie the Rac
A mischievous raccoon that was adopted by Slim until he was set free. He comes back to the ranch sometimes and stirs up trouble.
Rip and Snort
Two coyote brothers who often pester Hank.
- Exit Pursued by Two Coyotes: If Hank is facing another one of his enemies (Such as Sinister the Bob Cat or Buster and Muggs), he can cause the two villains to fight each other until Rip and Snort chase them off.
- Those Two Bad Guys: They're always together in any book they appear in.
- Villain Song: Several, "We Don't Give a Hoot!", "We're Proud to be Ignoramouses", and "The Cannibal Way" are some examples, but the most recurring is the "Coyote National Anthem and Hymn"
- The Voiceless: The most that comes out of Rip's mouth usually is some form of "Uh!", which is used as an affirmation or a disagreement depending on the situation. Granted, there are times he gets more eloquent, but they're few and far between.
- You No Take Candle: This is the way they (and other coyotes) always speak.
A female collie who lives near Hank's ranch, and one of the objects of Hank's affections.
- Damsel in Distress: In The Case Of The Kidnapped Collie.
- Nice Girl: She tries to be considerate of Hank even though she can't return his feelings and during one book when Drover starts yelping about his leg, she shrieks and tries to help, even scolding Hank (who knows it's fakery) for being uncharitable in his remarks on the subject.
- Sickeningly Sweethearts: She and Plato have some lovey-dovey nicknames for each other.