In the Star Wars saga, Luke Skywalker received piecemeal training from a number of Jedi, both in canon and Legends. Yet, despite being one of the most powerful Jedi in the galaxy, Luke Skywalker received very little dedicated formal training in the way of the Jedi. For the most part, Luke’s strength in the Force and skills with a lightsaber came from self-teaching, experimenting, and, depending on the continuity, repeated close-call encounters with more experienced dark side warriors (aside from Darth Vader). Luke’s wisdom and fighting prowess are proof of his incredible natural aptitude with the Force, not unlike his father, Anakin, and his eventual student in the current canon, Rey. That said, the few beings he did train under left a lasting impression on Luke, both as a person and as a Jedi.
The two most famous Jedi who trained Luke were Jedi Masters Obi-Wan Kenobi and Yoda, who gave Luke something of a crash course version of their traditionally decades-long Jedi training regimen. In between Obi-Wan’s brief lessons in Star Wars and Yoda’s stricter courses in The Empire Strikes Back, Luke sporadically self-trained during his three years in the Rebellion. In both the current canon and the Expanded Universe (now known as Legends), Luke had several encounters with experienced Force-using opponents and Darth Vader himself. Each time, Luke either barely managed to prevail or simply survived long enough to escape, but he also learned more about lightsaber combat and Force wielding from the encounters.
After his devastating defeat in The Empire Strikes Back but before the rescue of Han Solo in Return of the Jedi, Luke continued to self-train, building his own lightsaber (a vital rite of passage for Jedi) and growing in both strength and maturity in preparation for another duel with his father. It may have been for the best that so little of Luke’s training came from his mentors as it was Luke’s decision to do what he felt was right in his next encounter with Vader that solidified his father’s redemption. Had he listened to Obi-Wan and Yoda and killed Vader, Luke likely would have fallen to the dark side and continued The Emperor’s tyranny as a Sith.
In Legends, not all of Luke’s mentors were Jedi. In Dark Force Rising, Luke sought further Jedi training from Joruus C'baoth, who Luke believed was a Jedi Purge survivor who could help him rebuild the Jedi Order. In reality, C'baoth was an insane, dark side-corrupted clone of a Jedi who died before the start of the Clone Wars. Unsurprisingly, Luke’s training from the unstable clone was brief. In Dark Empire, Luke seemingly fell to the dark side and became the apprentice of the reborn Palpatine. This corruption was not genuine, however, as Luke was feigning his fall to the dark side as part of a plan to undermine the Sith and the Empire from within.
Obi-Wan Kenobi
A veteran of the Clone Wars and mentor to Luke’s father, Anakin, Obi-Wan “Ben” Kenobi watched over Luke during his formative years on Tatooine, occasionally keeping him safe from dangers such as Tusken Raiders and Krayt Dragons. Kenobi tried on several occasions to introduce Luke to the Force, but his attempts to mentor him were vetoed by Luke’s Uncle Owen, who wanted Luke to avoid ending up like his father. It was after Imperial stormtroopers murdered Luke’s aunt and uncle that he accepted Obi-Wan’s offer to train him as a Jedi.
Luke only had a few brief lessons with Obi-Wan Kenobi before the latter’s death at the hands of Darth Vader, but Luke was able to learn some basic lightsaber techniques and take his first steps into opening himself up to the power of the Force. It was because of Obi-Wan’s lessons, combined with Luke’s own self-training, that he was able to defeat (with extreme difficulty) opponents such as the Sith Warrior Kharys, who was trained by Darth Vader himself.
Years after Kenobi’s death, Luke received one last lesson from the late Jedi Master: how to construct a lightsaber. In Legends, Luke spent over a month living in Kenobi’s Tatooine home, reading a journal he’d left for Luke that included instructions for building a Jedi weapon. Luke’s lightsaber hilt was almost identical to Kenobi’s Clone Wars-era weapon, likely in honor of his first mentor. Luke would again honor Kenobi by naming his son Ben Skywalker.
Yoda
The majority of Luke’s formal Jedi training came from the 900-year old Jedi Master Yoda. In The Empire Strikes Back, Luke Skywalker's Jedi training took place on Dagobah, learning more advanced lightsaber techniques and strengthening his connection to the Force during the ancient Jedi’s training courses. Yoda’s training taught Luke many harsh lessons and showed the prospective Jedi how much he still had to learn. In many cases, such as Luke’s dark side encounter in a cave and his inability to lift his X-Wing from a swamp, Luke learned his lessons through failure.
In Legends, Luke takes his failed lessons to heart, learning to approach problems with patience. More evidently, he learns from Yoda’s own failures as the previous Jedi Grandmaster. As the founder of the New Jedi Order, Luke looked to the failings of the previous generations of Jedi as pitfalls to avoid once the Jedi returned. Luke’s Jedi were not monastic warriors so far removed from the people of the galaxy that they resided in an almost literal ivory tower. Instead, they were ordinary beings with their own lives outside of the Jedi Praxeum. They could fall in love, own possessions, and believed that even those who fell to the dark side were not necessarily too far gone for redemption. Luke and Yoda’s failures taught the former how to establish the ideal iteration of the Jedi Order.
In the current canon, Luke evidently did not learn from his failures during Yoda’s training, and his contributions to Ben Solo’s fall to the dark side mirrored the mistakes of Obi-Wan and Yoda in their lifetimes. Because of this, he received one last lesson from Yoda, now a Force ghost. Here, Yoda repeated to Luke that he needed to learn from the failures of himself and his predecessors and pass on those lessons to the next generation. Few details are known about Luke’s generation of Jedi in the current canon, but this implies that Luke repeated many of the same mistakes Yoda’s generation had made, leading once again to the Jedi’s near-extinction. Luke did redeem himself after this lesson, however, and distracted his nephew to buy time for the Resistance to escape the First Order as his final act. In the final installment of the Star Wars saga, Luke joined his Jedi mentors as a Force ghost in lending their strength to Rey during her final confrontation with her grandfather, Palpatine.