I'm going to make a wild assumption here, and guess that his bedroom door is left open when you tuck him in for the night, and maybe even a nightlight.....
If that is the case, this is what I did with our son. Threaten him. LOL
But seriously. Tell him (and follow through if he tests you, b/c he WILL test you at least once) that if he gets out of bed again (I'd do this on his 2nd time popping out of bed, not the first) that you will close his bedroom door and he will have to go to sleep with the door closed. Since he won't stay in bed, the door will be closed. (or you will turn off the nightlight--whatever his crutch is).
Matter of fact. No anger. You can even sound sad if you want, but no anger.
It worked like a charm for my son. I think I only had to do it one time. He never used a nightlight, but hated having his door closed.
I also used the "I'll come back to check on you in a few minutes, AS LONG as you stay in bed." He wanted me to come back, so he stayed in bed. And I would keep my promise. Almost like sleep training with a toddler... I'd come back after about 5 minutes, and stand in the doorway for a moment. If he was still awake, I'd walk over and kiss his forehead and say "I love you, now go to sleep. I'll come back and check on you again after you are asleep."
And I would. At first, he would still be awake every time, and so I'd just stand in the doorway for a moment, whisper "go to sleep. I'll check on you after you're asleep, too." and then softly walk away. This might happen a few times. At first 5 min. Then 10 min. Then 15 min. Usually by then, he was asleep. So I'd kiss his cheek or forehead and leave.
The next morning I would tell him that I HAD come back to check on him like I promised. After awhile, I wouldn't go back to check on him so quickly. I'd tell him I had to _____ (fold some laundry, empty the dishwasher, clean up in the kitchen, etc---anything he could hear me physically doing something, so it would feel like I was near even though he couldn't see me), and THEN I would come back and check on him. Very soon, he would be asleep the first time I came back to check on him.
He is making it a game, b/c he wants to avoid bed, and you aren't enforcing the bedtime in a way that makes it not fun for him. Figure out his "currency" at bedtime. For my son, it was leaving the door open vs. closing it for non-compliance. Maybe your son has a lovey that can't sleep with the constant up and down jostling when your son is getting in and out of bed? So maybe you need to put the lovey in YOUR room, or on the sofa, or in the closet, so that he can get a good night's rest..... (it sounds mean and harsh---but it only takes ONCE and he will understand that it is completely within his control to keep his lovey, or the door open, or ________). Don't give multiple warnings. Just tell him UP FRONT what will happen if he gets out of bed again. (warningS are when you tell him the consequences AGAIN, after he has repeated the offense, but you don't implement them THIS time).
"Billy, this isn't a game. If you get back out of bed again tonight, without going to sleep, BooBoo Bulldog is going to go to the guest room to sleep, because he can't fall asleep with all the commotion of you getting in and out of bed. Stay in bed and he can fall asleep with you. Get out of bed again, and you will stay here and he will go to the guest room."
Billy gets up again: (say nothing to him directly) "BooBooBulldog, come on, let's go get you settled in the guest bed, so you can get a good night's sleep. If Billy stays in bed, I will bring you back to sleep with him then." (then to Billy: "Sorry Billy, he isn't getting a good night's sleep in here. Now get back in bed and go to sleep. After you fall asleep, I'll bring BooBoo back and tuck him in with you") and leave.
He will cry and be upset, maybe. But he won't let it happen again tomorrow night.
ETA: oops... I took too long typing. I guess the door assumption was wrong, huh? lol Has he got a lovey?