Is he cranky? Does he seem tired all the time? If not that may be all he needs. If he does seem cranky all the time you may be putting him down too late. I would watch for signs of tiredness, which I am sure you know about since you have three kids. When my son is over tired he does not sleep well at all. His signs of tiredness are glazed look, ear pulling, and then eye rubbing. Once he whines/cries I have started to miss the window and he starts to get overtired. It seems that 10 is way too late for a bedtime. Sleep begets sleep, so if he gets good sleep during the day he will sleep better at night and visa versa. Since your other kids slept better maybe he needs a bit more help. Do you have a nap/bedtime routine? Is his room dark? Maybe a sound machine would work? You may want to provide a bit more info so that others can share ideas with you.
I am responding again. My son is now crawling etc and it seems that he has a hard time transitioning from playing, crawling, laughing, etc to laying in bed and going to sleep. Therefore, we have a routine to wind down. We read him two stories (I read while I nurse and my husband reads and baby has a pacifier), we then turn off his light and turn on the sound machine, last we hold him in the dark and sing him a song or two. You can feel his body relax and sometimes he will put his head on our shoulder, then we put him in the crib. I know you have other kids and may not have time but maybe he needs a transition time from play to sleep. I hope you get some advice that will work for you and the family. Good Luck.