One major difference between King Saul in 1 Samuel and Creon in Antigone is that Saul is evidently far more easy to convince of holding a poor opinion than Creon. When Saul decrees that his son Jonathan will die for breaking Saul's foolish command not to eat anything until Saul has had his revenge on the Philistines, the Israelites speak up in Jonathan's defense, calling him a hero of Israel. The people argue that since Jonathan has delivered the people from the Philistines on that day, Jonathan was surely working alongside God that day, regardless of breaking his father's command, as we see in the lines:
Must Jonathan die, who has brought about this great deliverance in Israel? Far from it! As the Lord lives, not one hair of his head shall fall to the ground, for he has worked with God this day. (14:45, NASB)
The Israelite's protest against killing Jonathan apparently worked on Saul very quickly for the next line says, "So the people rescued Jonathan and he did not die" (14:45).
In contrast, Creon was not as easily convinced by his people. After Creon proclaims Antigone's death sentence, Creon's son Haemon comes to him telling him to reconsider because the whole city is mourning for Antigone and saying that she does not deserve to die, as we see in the lines:
... for the common men out of fear of your face won't say such words as you would not rejoice to hear; but I can hear these things in darkness, how the city weeps for this girl, says she's the least worthy of all women to die so badly for such noble deeds. (701-707)
Haemon further tries to reason with his father and get his father to accept another's opinion other than his own. However, unlike Saul, Creon will not be moved by the people. Creon even reveals his tyrannical nature by going so far as to say that he will not be ruled by his own city. Creon only eventually decides to listen to others' advice after Tiresias prophesies doom for the city from the gods for Creon having dishonored them, but by then it is too late.
Another difference in character between Saul and Creon is that Saul makes many efforts to always please God, while Creon never thinks about his own decree as breaking the gods' laws and dishonoring them. We see Saul try to honor God when, after seeing the Israelites break a commandment, he has them offer up a sacrifice to appease God. In contrast, when Creon is reminded by both Antigone and Tiresias that he has dishonored the gods, Creon's response is to say that he refuses to be ruled by either Antigone, Tiresias or even by fear of the gods.