Study leader Michael T. French, professor of health economics at the University of Miami, and colleagues found a high school grade point average was a strong predictor of future earnings.
"Conventional wisdom is that academic performance in high school is important for college admission, but this is the first study to clearly demonstrate the link between high school GPA and labor market earnings many years later," French said in a statement.
The findings, published in the Eastern Economic Journal, also found that African-American men and women achieved more education than white students with the same high school GPA and characteristics.
"The results suggest that African-Americans with poor high school GPAs are less likely to graduate from high school and attend college, but once GPA and other factors are included in the models, they are actually more likely than other races to graduate from college and continue to graduate school," French said.
"One possible explanation for this finding is that African-Americans with relatively high GPAs are more motivated and determined than whites to attend college and obtain an advanced degree."
The study also found overall high school GPA was significantly higher among women, but men had significantly higher annual earnings.