Kraglin was born on the planet Xandar. He eventually grew up to become a Ravager and the first mate to Yondu, even when Yondu took in Peter Quill (known as Star-Lord) as his protege. During the years, Kraglin developed a rivalry with Peter.
When the Ravagers sought to collect the Orb (containing the Power Infinity Stone), they are upset to hear that Peter has beaten them to it and intends to sell it to the Collector. As such Kraglin willingly obliged to Yondu's orders to capture Quill at all costs. However, when they finally do so, Peter warns that the Orb has been stolen by Ronan the Accuser, who intends to use it to lead a Kree invasion on the planet Xandar, and that the Ravagers must help the Guardians stop the invasion in exchange for the Orb.
Reflecting of the time when he was sold to the Kree as a child slave, Yondu accepts the deal. To that end, Kraglin piloted his own ship alongside Vorker and helped shoot a hole in the side of Ronan's ship, allowing the Guardians to enter the ship and fight off Ronan's soldiers. Following Ronan's death, Peter hands over the Orb to Yondu, who leaves away with Kraglin and the other Ravagers. As Kraglin and the Ravagers are celebrating their victory against Ronan, they are unaware that the Orb actually contains a Troll doll inside while the real Orb is handed over to the Corps, though Yondu actually seems to be pleased by this.
Guardians of the Galaxy Vol. 2
Kraglin is seen enjoying his stay at the planet Contraxia with his fellow Ravagers, where Taserface questions of Yondu's softness towards Peter. Eventually, the arriving Sovereign High Priestess Ayesha met the Ravagers and offered them a reward for the capture of the Guardians of the Galaxy for the theft of the Anulax Batteries.
Kraglin went with the other Ravagers onto Berhert, where they manage to capture Rocket Raccoon and Groot as the other Guardians were being transported into the planet Ego. However, Rocket offered a deal to the Ravagers: he'll give them the batteries in exchange for his and Groot's safety, a deal that Yondu accepted by warning that killing the Guardians would put the entire Ravager clan in trouble with the Nova Corps. Though several Ravagers obliged to Rocket's deal, Kraglin proceeded to question Yondu about his care towards Peter (despite the latter's earliest actions), but this only motivated Taserface to led a mutiny against Yondu and his followers, even after Yondu and Rocket are knocked out by a freed Nebula, something which a horrified Kraglin didn't expect.
Kraglin is then forced to watch in shame as he witnessed Taserface, Gef, and other Ravagers humiliate Yondu, Rocket and Groot. He is even more horrified to see them killing off the Ravagers who remained loyal to Yondu (including Tullk and Oblo). Feeling remorseful for letting this happen, Kraglin sets the captives free while admitting that he had no intention in allying himself with Taserface. As Yondu and Rocket finish off Taserface and the mutineers in revenge for their treachery, Kraglin activates an escape pod for himself, Yondu, Rocket, and Groot to head over to the planet Ego. During the trip, Yondu explains to Rocket that Ego is Peter's biological father and that he intends to use Peter's Celestial power to expand himself and take over the universe for himself. Yondu also admitted that he, Kraglin and the other Ravagers were paid to deliver Ego's offspring to Ego (which was against the Ravager code) and that they later quit after learning that Ego has killed the offspring since they didn't possess any Celestial powers.
After arriving to Ego's planet, Kraglin is ordered to stand on watch as Yondu, Rocket, and Groot head to rescue Peter and stop Ego. Kraglin even warned the heroes of the arriving Sovereign armada (since Taserface gave them the coordinates of the escape pod before he died), though Yondu and Nebula foiled this by utilizing their ship's lasers to destroy the Sovereign armada for good. Following Ego's death, Kraglin sets his ship to rescue the Guardians from the imploding planet while Yondu sacrifices himself to save Peter.
Following Yondu's funeral, Kraglin gave Peter a Zune, and in return, Peter gave Yondu's arrow to Kraglin, saying that Rocket fixed it and that he decided Kraglin would want it. With a newfound respect, Kraglin thanked and acknowledged Peter as his captain. He is even delighted to see that the other Ravager clans (contacted by Rocket) have arrived to pay their respects to Yondu in honor for his actions.
During the credits, Kraglin is seen fitting himself with Yondu's fin as he practices using Yondu's arrow with his own whistles. However, the arrow accidentally pierced into Drax's chest (though not fatally), much to Kraglin's horror and embarrassment.
Kraglin was horrified to learn that most of the Guardians (except for Rocket and Nebula) were killed by Thanos alongside half of the universe's populace, and that Thanos destroyed the Infinity Stones to ensure that the death wave won't be reversed before he was killed by Thor. However, five years later, the Avengers went back in the time to collect the Stones and the reverse the death wave, bringing those who have perished back to life (including the other Guardians).
Eventually, the 2014 Thanos soon learned about this and traveled to the future with his vast armies of the Black Order, Chitauri, and Sakaaran Mercenaries, intending to use the Stones to wipe out the entire universe and recreate it in his own image. Not wanting to let this happen, Kraglin pilots his own ship as he leads his own army of Ravagers to help the Avengers and Guardians fight against Thanos and his forces, which eventually ends with Iron Man sacrificing his life in using the Stones to destroy Thanos and his forces for good.
It can be implied that Kraglin returned to his life as a Ravager following Iron Man's funeral.
As of currently, Kraglin is one of the two surviving members of the Yondu Ravager Clan alongside Peter, though Peter would later be killed by Thanos in Avengers: Infinity War before being revived back to life in Avengers: Endgame.