This is a 1947 story of a homeless man who house-sits every winter for a wealthy man who spends winters in his other home. The problem is that the wealthy home-owner doesn't know his house is hosting a "guest" every year. This year, the unofficial house guest ends up letting several other people move in with him, including the disguised home owner. It's a bit slow moving but a pleasant low-key holiday film.
Here's a short clip that puts together a couple of scenes:
DVD Talk says,
Roy Del Ruth's It Happened on Fifth Avenue is a hive for double, triple, and quadruple-layered situational humor, easily one of the best of its kind and a real gem of a holiday picture.TCM has an overview. MUBI has some information.