Previous cross-sectional research shows that not all Latino immigrant youth are becoming American. Some immigration scholars, in fact, partly attribute Latino heterogeneity in American identity to disparate perceptions of discrimination. However, little is known about the variable relationship between perceived discrimination and American identity as youth transition from early to late adolescence and into adulthood. To fill this void, this analysis employs data from the Children of Immigrants Longitudinal Study (CILS) to examine the extent to which unequal perceptions of discrimination explain Latino variation in American identity as well as the changing effects of perceived discrimination over the life course. Results from random-effects logistic regression models indicate that although disparities in perceived discrimination do not explain subgroup differences in becoming American, it has a significantly negative effect on the likelihood of identifying with an American label, even when controlling for family background and traditional acculturation measures. Moreover, this study finds that the effect of perceived discrimination is only significant during early adolescence relative to late adolescence and adulthood. Implications of these results for immigrant adaptation and suggestions for future research are discussed.