As a stowaway aboard the Jupiter 2, Dr. Zachary Smith (Gary Oldman) becomes an unwitting participant in the Global Sedition conspiracy to murder the Robinson family along with any witnesses to that fact. Clearly, he has no qualms with killing the family, toasting them with "Give my regards to oblivion." It's when he is slated to die along with them that he starts to take offense to the plan.
The Robinsons, led by patriarch Prof. John Robinson (William Hurt), are set to travel to Alpha Prime through a new Hyper-Gate in search of resources to help the people of Earth as their own planet is seemingly running dry. Opposed to this, the Global Sedition hires the snivelling Dr. Smith to do their dirty work and sabotage the Robinson ship. Once his work has been done though, he is trapped aboard by his own employer, to be disposed of in deep space.
Dr. Smith wakes up the cryo-sleeping Robinsons in time for them to save the ship - well, little Will does - and helps revive their daughter Judy from certain death. They don't trust Smith though and lock him up in a makeshift brig. Eventually, though, he becomes a reluctant part of the team to help them explore a brand-new quadrant of space, having engaged the hyperdrive in an emergency without a destination Hypergate to guide them. Now marooned in deep space, the Robinsons must find a way home and will need Dr. Smith's help too.
Everything changes (again) when the Jupiter 2 lands on a strange planet and Dr. Smith suffers an injury which mutates him into a giant spider-like creature. We only see the aftermath of this: a dead family, save for Will who has grown into a true genius, building a Hypergate completely from scratch to return to Earth. It is the spidery Dr. Smith, however, who plans to use the gate, readying himself to travel back to wipe out the planet and take over the world with his spider offspring. In the nick of time - so to speak - Will is able to use the Hypergate to speak to his family in the past and warn them of the impending doom. For Dr. Smith, it would seem a bittersweet destiny: his plans for world domination are thwarted, but at least he doesn't turn into a spider.
INTELLIGENCE - 7: This doctor is clever, inventive, and crazy like a fox.
POWER - 3: Mostly, he seems to be a scared weakling, but he's just fully aware of his own physical limits.
VILENESS - 10: Willing to murder the Robinson family for the Sedition cause and his own profit. And then he killed them anyway.
SWAY - 6: Keeps people off-guard with his skittish behavior, all the while looking for his chance to stab anyone in his way in the back.
PURITY - 8: Greedy and slimy, he's only willing to work with the Robinsons when his own survival hangs in the balance.
PHYSICAL - 4: Pencil-thin and scruffy, it looks like a strong gust of wind could knock him over. Until he turns into a spider, that is.