Research from the U.S., says that being a 'happy chappie' is as effective as talent, hard work and commitment in helping people reach the top.
The discovery turns upside down the theory that it is success that makes people happy.
According to the research by Sonja Lyubomirsky, of the University of California - Riverside, consistently happy people are more likely than others to be successful in life and love.
The finding puts paid to the myth that it is success that makes people happy, and not the other way round.
The lead author of the paper Lyubomirsky says that it is clear that happy people were, in general, more successful than less happy people in many aspects of their life.
She suggests that this may be because happy people frequently experience positive moods, and these positive moods prompt them to be more likely to work actively toward new goals and build new resources.
When people feel happy, they tend to feel confident, optimistic and energetic, and others find them likeable and sociable.
Happy people are thus able to benefit from these perceptions.
Dr Lyubomirsky and her co-authors, Laura King, of the University of Missouri-Columbia, and Ed Diener, of the University of Illinois and The Gallup Organisation, reviewed 225 research papers on happiness that covered 293 samples and 275,000 people and computed 313 significant findings.
Despite the many definitions of happiness used in research literature, ranging from “life satisfaction” to “momentary feelings of pleasure”, Lyubomirsky's team stayed with “the frequent experience of positive emotions”, as they found that what mattered most was the length of time that people experienced happiness, and not necessarily the intensity of that happiness.
The authors found that cheerful job applicants were more likely to secure interviews and to be evaluated more positively once they got a job.
They also were less likely to show burn-out and more likely to have jobs with autonomy, variety and meaning.
The team discovered that one study included in the research found that happier cricket players had higher batting averages, while another indicated that happy sales forces had the most satisfied customers.
Happy workers were less likely to take time off work and, in general, earned higher incomes, and were shown to have more friends and better personal relationships and health.
However they did discover some drawbacks to being happy; cheerful people appeared be worse at problem solving, maybe because they were so relaxed and did not always learn from trial and error.
Also because they were more likely to think that everything was always going well, they could also be worse at critical thinking and error checking.
Another potential drawback spotted was that consistent happiness presented the danger that happy people could slip into hedonism or inappropriate risk taking, whereas mildly depressed people were most likely to excel in jobs such as monitoring a nuclear power plant, where constant vigilance for possible problems was essential.
The finding is published by the American Psychological Association.