Captain Jonathan Archer (Scott Bakula)

The Captain of Earth's first Warp 5 starship, Archer had spent most of his life dreaming of going to the stars. And since his father was a major player in humanity's achievement of Warp 5 in the first place, his command is rather personal. This is also where he got his distrust of Vulcans, as they had spent most of his life attempting to keep humanity in and around its own solar system.
Subcommander (later Commander) T'Pol (Jolene Blalock)

"If we expect to continue our relations with Humanity, we have to earn their trust."
Archer's Vulcan science officer and
second-in-command, T'Pol did not like humans when she first joined
Enterprise's crew. Of course, as the years wore on, she came to respect her human crewmates more and more, and shifted her loyalty from the Vulcan High Command to Starfleet and, more specifically, Captain Archer, with whom she would develop a strong friendship. (Falling in love with Trip Tucker certainly didn't hurt, either.)
Commander Charles 'Trip' Tucker III (Connor Trinneer)

"You expect us to sit up here for a week while the probes have all the fun?"
Enterprise's Chief Engineer and Archer's long-time best friend, Trip Tucker's "good ol' boy" Southern charm disguised one of the sharpest minds in Starfleet. Between his engineering genius and security head Malcolm Reed's deep and lasting desire to blow things up,
Enterprise kept flying even when she probably shouldn't have and exceeded all expectations in the process.
Lieutenant Malcolm Reed (Dominic Keating)

"This is called a phase pistol. It has two settings: 'stun' and 'kill.' It would be best not to confuse them."
British, shy, quiet and reserved unless someone was in danger, Reed had a talent for getting himself injured while trying to protect his crew and his captain. As it turns out, he also had a talent for blowing things up, and with Trip's engineering genius, did it much better than the weapons specifications said he should have been able to. Although he started out isolated from everyone, he went on to develop a strong friendship with frequent verbal sparring partner Trip and became an anchor for Archer during the Xindi crisis.
- Ambiguously Gay: Dominic Keating is on record as saying, "God knows I played him gay!" but no one's sure whether he's joking or not. There is some evidence that Reed was slated to be the first gay character in Star Trek, but this was apparently later revoked. Considering he's had significant Ho Yay with at least three characters (Archer, Tucker and Hayes), however, Keating may not have been joking all that much.
- It's worth noting that when the Enterprise was sent back in time, Malcolm never got married or had kids, and he was the only member of the main cast (and possibly the whole crew) that didn't.
- Badass
- The Big Guy
- Dark and Troubled Past
- Deadpan Snarker
- Genius Bruiser: Despite being a technical genius when it comes to weapons, Malcolm really doesn't mind using said weapons.
- Hates Being Touched
- Ho Yay: With Archer, Tucker and Major Hayes, at the very least.
- Military Brat
- The Mole: Although to be fair, it wasn't precisely his fault.
- The Quiet One
- The Security Officer
- Shrinking Violet: Except where his crew's safety is concerned.
- The Stoic
- Stuff Blowing Up: 90% of the time, when Reed is openly happy/gleeful about something, it's related to weapons — usually using them.
- The Unfavourite: His father was a life-long Navy man, and has remained aloof, cold and generally disappointed in Malcolm because he didn't follow the family tradition (Malcolm's afraid of water).
- Well Done Son Guy: See The Unfavourite. He starts to thaw out a bit once Archer makes a point of befriending him.
Doctor Phlox (John Billingsley)

"I must admit, I wasn't planning to stay this long, but the opportunity to observe your species on their first deep-space venture has proven irresistible."
Enterprise's Denobulan doctor, Phlox had a habit of using alien creatures to assist in healing and a curious interest in human "mating habits." Luckily for the crew, he was also quite good at keeping them alive.
Ensign Travis Mayweather (Anthony Montgomery)

"I couldn't call a place home unless it came with a pair of warp nacelles."
Enterprise's pilot, Travis Mayweather was a "space boomer," born on one of the slow-moving cargo transports launched right after humans discovered warp flight. Since transports usually took years to get between ports, Travis grew up on the cargo ship ECS
Horizon and probably knows more about living in space than anyone else on board. This also translated into a talent for flying spacecraft.
Ensign Hoshi Sato (Linda Park)

Not a fan of space travel, getting eaten, or aliens, Hoshi Sato was on
Enterprise for one reason: She had an unmatched gift for languages. In the days before the Universal Translator, she was a critical part of
First Contact missions, especially since
she would go on to invent the aforementioned Universal Translator.
- The Chick
- Crowning Moment of Awesome: The Reptilian Xindi abduct her and use brain parasites to force her to decrypt the Aquatic Xindi activation codes for their superweapon. When she gets access to the code, she fights off the brain parasites, re-asserts her willpower, and adds even more encryption. When Dolim realizes what she's doing and drags her off for a second dose of brain parasites, she tries to throw herself to her own death. It doesn't work, and in the end, she does decrypt the access code, but by then, The Cavalry has had time to show up.
- Cunning Linguist
- Fake Nationality: Hoshi is played by Linda Park, a Korean-American actress. In the show, Hoshi is from Japan and speaks perfect American-accented English because she's the world's greatest Cunning Linguist.
- The Gift: Hoshi is not just a Cunning Linguist; one telepathic alien points out that it seems that her brain is uniquely wired for multiple languages.
- The Heart
- Hollywood Nerd
- Ironic Fear: Anything space-related. This was later echoed by Bones McCoy in the Abrams Trek film.
- Me Love You Long Time / Really Gets Around / The Starscream: In the Mirror Universe. As the crew put it, the episodes "Put the Ho back in Hoshi."
- Meaningful Name: "Hoshi" means "star." "Sato" means "journey." Therefore, "Hoshi Sato," more or less, translates to Star Trek.
- Omniglot
- Shrinking Violet
- Took a Level in Badass: Hoshi suddenly acquires martial arts skills in Season 4.
- In the penultimate episode, the former Shrinking Violet commands the ship, takes on the President of Earth in a battle of the wills and wins. (Which sort of suggests that Starfleet is a bit too comfortable with ignoring the civilian government. Might explain why every third admiral was planning a coup from ST VI on.)
- In the Mirror Universe, Hoshi, a puny human who's built like a twig, is somehow able to defeat a superhumanly strong Vulcan in unarmed combat with little difficulty.
- Ahem: Rule Of Cool, Rule of Sexy, and this is mirror Hoshi; it makes sense she knows how to defend herself.
- She becomes Empress soon after. That's why.
- Twofer Token Minority
Porthos

Archer's utterly adorable beagle.
Admiral Maxwell Forrest (Vaughn Armstrong)

The crew's
Reasonable Authority Figure based on Earth, Forrest was
also not a fan of Vulcans. He was, however, Archer's friend and patron, and was unusual for an Admiral in that he actually
helped the crew instead of hindering them.
Soval (Gary Graham)

"We don't know what to do about Humans. Of all the species we've made contact with, yours is the only one we can't define. You have the arrogance of Andorians, the stubborn pride of Tellarites. One moment, you're as driven by your emotions as Klingons, and the next, you confound us by suddenly embracing logic."
The Vulcan ambassador, he doesn't trust humans one bit and attempts at all costs to stump them at every turn. T'Pol was his original partner in crime, until she
became the mask and decided she'd rather throw her lot in with the humans.
- Ambadassador: He has since left that part of his life behind, but a hundred years before the start of the series Soval was a member of the Intelligence division of the Vulcan High Command. He negotiated one of their original treaties with the Andorians while he was stationed on an occupied planet as part of the occupying forces, and when he returns to that same planet a hundred years later he is able to keep walking and shooting (Albeit without hitting anything) even after having been shot.
- Ass In Ambassador: Soval is an annoying Jerkass until Admiral Forrest gets killed off trying to protect him in the fourth season. Then he cooperates with Archer. And even then, he's kinda pushy.
- Obstructive Bureaucrat

"Tell Archer that's two he owes me!"
An Andorian space captain, Shran was slated to become an
Enterprise regular in the unproduced fifth season. Sadly, the show was cancelled before this could happen.
- Byronic Hero: In fact, ALL Andorians are walking Romanticism incarnate, praising emotion and the experience of passion, ritualizing the concept of a "duel" to settle differences, housing probably the greatest Art Academy in the United Federation of Planets...and thoroughly disagreeing with Vulcans (Realists and Rationalists).
- The Cavalry: Shows up in the nick of time and destroys a Xindi warship that was about to shoot down Archer's shuttle, which in turn would have allowed the superweapon to destroy Earth unopposed.
- Debt Detester: Specifically, to Archer.
- Face Heel Revolving Door
- Hero of Another Story
- Large Ham
- Proud Warrior Race Guy
- With Friends Like These: Although arrogant, militant and speciesist (his favorite nickname for Archer is "pinkskin", and he loathes Vulcans and Tellarites), he has a strong sense of personal obligation and provides more practical help than humanity's Vulcan "allies" during the Xindi crisis. Nevertheless, Shran often causes as many problems as he helps to solve.
Captain Erika Hernandez (Ada Maris)

"I'm married to Starfleet...just like you."
Archer's old flame and the captain of
Enterprise's sister ship
Columbia (NX-02), Erika Hernandez was a fiery
Action Girl who appeared in only three episodes of the show. Somebody liked her, though, because she shows up as a main character in the
Star Trek: Destiny novel trilogy — and, if you consider the
Star Trek Expanded Universe canon, plays a rather sizable role in the history of the Federation. (Spoilers for
Destiny are marked.)
Silik (John Fleck)

Future Guy (James Horan)

Daniels (Matt Winston)
Dolim (Scott MacDonald)
Dr. Arik Soong (Brent Spiner)
John Frederick Paxton (Peter Weller)