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Smitty started life in 1922 as a 13-year-old office boy (you may have seen him on this blog before). Here we see him in 1953, still working in the same office, though he has grown at least a couple years in the last three decades. Over the course of the 52 year run, Smitty would grow a full 10 years, though it seems that no one else in the strip would. The office girl Ginnie stayed the same age and Smitty eventually married her. Smitty's younger brother Herby also stayed the same age, and after Smitty and Ginnie married they became Herby's guardians. It's very odd how time works in comic strips.
I don't know a whole lot about the boss character, but everyone in the office seems to like him enough to want to chip in to get him a Christmas present. Or perhaps Smitty is just very convincing. Or maybe they think if they get him a present then he'll be nicer to them, or pay them better, or give them a lighter work load. It doesn't seem like that worked out very well.