He's old enough to start understanding a bit, so you just create a bedtime routine and talk him through it.
We had the same problem with my daughter, except that she refused to sleep in the crib after 2 weeks of life. The next 10 months she slept in bed with us, which meant that my "bedtime" was 7 PM for months! (I'd sneak out and go watch TV and do grownup stuff after an hour or so, when she'd be reliably too deep asleep to notice me leaving). Finally she got big and moved around too much for me to sleep comfortably (she always left daddy alone, ha!), so I started transitioning her to her crib.
I'm not gonna lie: she cried a lot. But crying it out was the only thing that worked for us with such a strong willed child. The pediatrician said as much ("if you've tried everything else, it's probably the case that the only way she'll learn is the hard way"). Within 3 nights, she had gotten the idea and would sleep on her own.
She's backslid every time she's been teething (will still sleep in her bed, but doesn't want mom and dad to leave the room), so we had to go through a few periods of re-training her to sleep alone, which thankfully means only a night or two of some crying. As she's gotten older, we've been able to talk her into it. "Now we've had bath, so we read. Now we read, and mom and dad give you a kiss, and it's time for sleep. Night night baby. We love you! See you in the morning!"
It might help to actually skip the crib for your little one and put him in a toddler bed (or a twin bed with a generous rail on the top part of the bed to make sure he doesn't fall out while sleeping), making it all about "now baby can get up out of the bed all on his own, and can play with his toys in his room!". That way, you emphasize the independence angle, which might appeal to him since he likes to slip out of your bed on his own.