The actor, who was recently reported to be in talks to remake French box office hit The Intouchables, made the comments when asked about the effects of modern Hollywood and the fashion world on beauty.
Firth told The Talks: "Well, there was a time when a beautiful person was considered something fine and to be celebrated.
"Now a beautiful person is assumed to be shallow and flaky. If you are beautiful in today's society, you are presumed to have no substance. I think a lot of talented and very bright people who are also physically beautiful have to work very hard if they don't want to just lean on their looks."
When the interviewer asked what he thought the reasons for this were, Firth replied: "I think there's resentment, there is the feeling that you can't have it all... I think someone that has the mind of a professor and also looks like Baywatch would just p*ss people off because they don't want them to have all of that."
The King's Speech actor also spoke about how he deals with the image-conscious film world, revealing: "I have someone who has dressed me right down to my socks... It used to be my wife, but then there are increasingly designers who offer you things and have great relationships with you and if you like what they do then it gets taken out of your hands."