I am a final year student who is really passionate to work in the management consulting industry. I have really good university grades (first class expected) but my high school results are not very great. I know that most consulting firms have a higher benchmark [than the grades I received]. I seem to get the feeling that they will reject me based on my high school grades.
I wanted to know whether companies would consider candidates such as myself who have an excellent university track record but not so great for high school?
If you went to a target school for university and did well, few people will care about your high school grades. The more recent data point outweighs the older data point. A useful corroborating data point will be any standardized test score or college entrance exam score. If such a score exists in your case, if it too is a good score, then I'd say your high school grades will likely be a non-issue.
If those scores are low, it might cause a firm to wonder which data point is correct - the university one or the high school one. If you get asked about high school grades, just ackowledge you know they are low and explain why they were low (not interested in school at the time, etc..). By the way, it's better to say you were "lazy (but smart)" than to say you worked super hard and all you could do was achieve the low grades.