Star Wars was always a space fantasy heavily influenced by myth with elements from many religious traditions. Among them it also has a Christian element, specific to the Easter time of year, that of redemption.
Redemption in the Movies
Anakin Skywalker

He was the best star-pilot in the galaxy, and a cunning warrior. I understand you’ve become quite a good pilot yourself. And he was a good friend.
Obi-Wan Kenobi tells Luke about Anakin in A New Hope.
In the initial first released Star Wars movie, we only know Darth Vader as the villain. All we know of Anakin is what Kenobi tells us.
The original trilogy reveals this only in the third movie, as we finally have confirmation that yes, Vader is Luke’s father. The Empire Strikes Back hinted at it, in the novelization it was fairly clear (and that no doubt based on an earlier draft of the final script) but Luke seems to sense it as truth though he still wants to deny it and asks Yoda for the truth.
You father was seduced by the dark side of the Force. He ceased to be
Obi-Wan to Luke in Return of the Jedi
Anakin Skywalker and became Darth Vader. When that happened, the good man who was your father was destroyed. So what I have told you was true… from a
certain point of view.
With the prequels we get more of the story. Anakin was indeed a good friend, strong in the Force and great pilot. He was generous, kind and knew nothing of greed. His mother was generous enough to let him go with the Jedi, knowing it was his only chance for freedom and to pursue his dreams. But Anakin’s mother could not have known the danger he face. The prophecy of the Chosen One and his powerful abilities wasn’t just of interest to the Jedi, but to their enemies. Palpatine, being a Sith, knew he had to get Anakin on his side, and he couldn’t force him. He had to pretend to be his friend.
Anakin’s visions of losing his mother, which preceded her death led to his losing control of himself and his powers and take a step to the dark side. This itself probably wasn’t a disaster, had he had confessed to Obi-Wan. But he feared the Jedi would cast him out at this (and the Council may have done so.) So he told his ‘friend’ Palpatine. He lost his arm, his friends, and was forced to hide his wife as Jedi were forbidden marriage.
But the final blow was having another vision, of his wife dying. Palpatine promised to save her. The Jedi did not. Anakin felt forced to choose between them. He betrayed and murdered the Jedi. But he didn’t get what he wanted.
And so in an effort to save her he turned on everything he loved, betrayed himself and ultimately, got her killed (albeit unintentionally.)
The Redemption of Anakin
Anakin had been happy at the idea of having a child (he didn’t know there were children.) So when Luke comes along his efforts to win Luke are just as they were to win Padme (if tempered by a reluctance to do permanent damage.) Luke wins Anakin back by passing the test his Father failed. Luke is willing to sacrifice it all, to sacrifice himself. The natural thing for many to do is to fight back when friends and family are in danger, even if it means using the wrong method to do it. But Luke realized the end doesn’t justify the means. If he has to become Vader to beat him, then he hasn’t really won or saved his friends at all. And so, while he fears for Leia and his friends he refuses to fight.
Anakin is once more faced with the choice. To remember who he was and be that man again, or let his son perish for the mistakes of his father. Anakin is redeemed at the final hour, fulfilling the prophecy by killing the Emperor. He saved his son, who was also a Jedi. He appears reunited with the Jedi in the end as a spirit.
While Anakin is the primary redemption arc in the saga, he isn’t the only one.
Lando Calrissian

Lando’s betrayal seems far worse than it actually is. orced to choose between the people of Cloud City who were his responsibility and leader and Han Solo his friend, he chose his people. Unfortunately he realized a bit late that he really hadn’t protected them from anything since Vader never intended to honor the deal.
It’s a harder thing for a child watching it to grasp for one thing, plus the original release, limited by budget and technology, didn’t show the full scope of Cloud City and it’s people. It was always indicated that it was a city, that the people were anxious to avoid the Empire’s attention. No doubt many of them for whatever reason were hiding there. Forced to choose between the people of Cloud City who were his responsibility as leader and his friend Han Solo, he chose his people. Unfortunately he realized a bit late that he really hadn’t protected them from anything since Vader never intended to honor the deal.
Lando sets out to redeem himself by rescuing Han from Boba Fett and Jabba and then by joining the Rebellion and leading the attack on the second death star.
It’s worth noting that the Expanded Universe also has some powerful redemption arcs.

Uliq Qel Droma
The most noteworthy is Uliq Qel Droma, because though his story predates the prequels, the story arc is very similar.
He begins as a Jedi, seeking to stop the spread of Sith secrets of Freedon Nadd from Onderon. He blames himself when the enemy who have uncovered Sith secrets attacks a Jedi Conclave and kills his Jedi Master, Arca Jeth.
His plan to infiltrate the Krath attackers, that the council has already rejected, remains firm in his mind. Going undercover, he attacks rebellious miners to ingratiate himself into the Krath elite (thereby killing presumed innocents.) Once there he is tortured with Sith poison and seduced by a the Krath Sith Sorceress. By the time his friends come
trying to pull him out he is already in to deep. Into this marches Exar Kun, initially to destroy him. But as he and Uliq both possess an amulet, it brings them together and soon Uliq is his Sith apprentice.
Uliq continues on this destructive course, now attacking the Republic itself, claiming allegiance of the Mandalorean clans, and finally joining Exar Kun’s destruction of suns near the Jedi world of Ossus. As the firestorm sweeps toward the world and Jedi evacuate, Cay Qel-Droma sees his brother coming in and tries to force him down. They fought, Cay pleading for him to come back. Uliq kills Cay. Shocked by what he has done, he has no time to recover before discovery by Nomi Sunrider who uses her powers to block him from the Force.
Uliq’s Redemption
A shaken Uliq takes the Jedi to Yavin 4 where Exar Kun is hiding. They unleash their powers and trap his spirit on that world.
Still, Uliq is a War Criminal. He wanders many years seeking to win back his powers, seeking redemption before giving up and finding a frozen world of Rhen Var. But fate isn’t through with him. A young Vima Sunrider, tired of her mother never having time to train her seeks him out to train her. He reluctantly gives in (for he can’t send her away) and finds peace. Nomi forgives him as he dies.
It’s interesting how close to how Anakin fell Uliq is: losing someone they care about, wanting power to prevent it happening again (Anakin – how to prevent death, Uliq – how to block their powers), killing the innocent (however understandable the motives ie they killed Anakin’s mother, the miners would’ve died anyway, finally both betray the Jedi), killing someone they loved.
His story is told in Tales of the Jedi: Knights of the Old Republic, Dark Lords of the Sith, The Sith War, Redemption. He also has a small part in the Clone Wars, a 2003 XBox game.
Gav & Jori Daragon

Gav and his sister Jori were orphaned when their cargo hauling parents were caught in a crossfire between in Empress Teta’s war with Rebels on her worlds. Their quest to become hyperspace explorers kept netting them little but bad debt until a vengeful merchant blamed them for his own choice of a route marked dangerous that cost him a shipment. Running for their lives, they stole their ship from Arrba the Hutt who held it for past repair bills. This time they found a viable route. Unfortunately, it led to the long lost Sith Empire.
Sentenced to death but ‘rescued’ by the ambitious Naga Sadow, they were separated and Jori tricked into leaving without Gav, who Sadow was teaching Sith magic too.
Gav meanwhile was convinced the people would be better off under the Empire. His doubts didn’t crystallize until leading the Sith fleet he landed at Aarba’s repair dock seeking Jori, and his guards killed their old hutt friend.
Gav and Jori’s Redemption
Jori escaped and tried to warn the Republic but their flight from debt and stealing the ship led her to a prison colony. Escaping she warned Empress Teta and gave focus to the Jedi’s dark visions. Jori, for her role in saving the day, was given Aarba’s repair dock.
Gav went to Naga Sadow and distracted him from his Sith battle meditation, but fell prey to a trick, stranding him near an exploding star. But his sacrifice and redemption allowed Empress Teta, the Jedi and Jori to go back to the Sith Empire and devastate their attackers at the source.
Their story is told in Tales of the Jedi: Golden Age of the Sith and Fall of the Sith Empire
Kyp Durron

Kyp was disadvantaged at the start, taken to the Kessel penal colony as a mere child where his parents died, and his brother was hauled off to be brainwashed into a Stormtrooper at the Carida academy. The closest he had to an ally was Vima Da Boda, former Jedi, who taught him some skills with the Force. Rescued by Han Solo, he starts at Luke’s Jedi Academy. But no one realizes before it’s too late that though Exar Kun was defeated there, his spirit remained and was able to make mischief. Influencing young Kyp, the young Jedi ripped an Imperial super weapon he and Solo had found out of the heart of planet Yavin and sent Luke Skywalker into a coma.
He set out to destroy the Empire for what they did to him. Heading for Carida, he fell for the lie that his brother had died in training and fired the super weapon at the son. Too late he found his brother lived. His rescue attempt was failed and all on the planet died.
Kyp’s Redemption
Back at the academy the Jedi trainees defeated the spirit of Exar Kun, and Kyp, devastated that he’d killed his brother and no longer under Kun’s influence, was brought to his senses by Han Solo. Returning to Yavin 4 to face Luke, he was put through tests which he passed. Then he helped destroy the sun crusher and a prototype death star weapon at great personal pain and sacrifice.
His story is told in the novels Jedi Academy Trilogy: Jedi Search, Dark Apprentice, Champions of the Force with some further action also in the novel Darksaber as well as the comic book Jedi Academy: Leviathan.
Cade Skywalker

The young boy he was trained as a Jedi. But when the Sith Empire joined forces with the Fel Empire (a mistake the Fel’s would regret) they destroyed the Ossus academy and his father fell in battle. He helped the other student’s escape but was lost in space and found by pirates who aimed to loot the place. Forced to pretend it had nothing to do with him, he had to leave his Father lie, unburied or cremated, as the pirates did as they would. They raised Cade and he became one of the crew.
Years later Cade was a bounty hunter, even turning in other Jedi for the reward with his best friend a man who hated Jedi, addicted to Death sticks and far from what he would’ve been.
But fate would not let the last Skywalker be, and he found himself forced back into the conflict, to choose to be Jedi (albeit an unusual rough edged one) or a Sith.
His story is told in Star Wars: Legacy
Revan

As Mandalore went to war against the Republic and the Jedi Council refused to get involved,the Jedi Knight Revan determined he would join the Republic war effort and take any other Jedi that would go. Among them were his apprentice Malek and his friend Meetra Surik.
But the war was devastating and soon afterward, on investigating what led to it, he and Malek fell to the Dark Side, turning and leading a large part of the Republic Fleet back against their former allies. The Jedi finally had to intervene, as Malek turned on Revan and fired on his ship, they boarded, captured him and erased his memory, enabling him to begin fresh.
As time goes on his memory is revealed as he picks up companions: Carth, Bastila (who was among those who captured him), Mission Vao, Zaalbar, T3 and even Canderous Ordo of the Mandaloreans. In the end stopping Malek is up to him.
Afterward though, he still has to face some hard truth: what made him turn, what has he forgotten. It’s important. In his quest to find out what made him turn…things will come out about the Sith and the Sith Empire that will change the galaxy forever.
His story is told in the game Knights of the Old Republic, with more revealed in the novel Revan, and in revelations in Knights of the Old Republic 2 and Star Wars the Old Republic video games. In the games you can choose for Revan to remain fallen, but the Expanded Universe canonical version is for him to return to the light.
Exile AKA Meetra Surik

War is seldom black and white. In saving people from the devastation of the Mandaloreans, the final battle of the war caused mutually assured destruction of both sides and created a ‘wound’ in the Force at the world of Malachor V. The Exile, lost or cut off from the Force and ordered away by the Jedi who felt joining the war was wrong had to make her own path.
But eventually she must return, and finds Revan is missing, the Republic crumbling do to an economy and ecologies ruined by war, and Sith have stalked and destroyed most of the Jedi.
There is only one thing to be done: Stop the Sith, find out what happened to the Jedi and how she can make right the wound that her last battle created.
Her story is told in Knights of the Old Republic 2
Atton

Atton’s fate depends on the Exile for he will follow her lead.
But he once served under Darth Revan, capturing and torturing Jedi. Then one captured Jedi warned him he himself could well end up in the same position for he had the power and he fled. But once he meets the Exile, he falls for her. And now his fate will be heavily influenced by her choices.
Now he can find redemption himself by stopping the Sith alongside the Exile.
His story is told in Knights of the Old Republic 2