Developing identities that are well-aligned with sociocultural expectations is a key psychosocial developmental task for adolescents and emerging adults. Most studies have examined identity development focusing on how individuals develop their identities (identity process), such as identity exploration and commitment. Meanwhile, researchers have emphasized incorporating the what of identity development (identity content) with identity processes to further the understanding of identity development in sociocultural contexts. This study focuses on the positive and negative valences of identity defined by desirable and undesirable images shared in sociocultural contexts. We investigated the bidirectional associations of identity exploration and commitment processes with positive and negative identity elements using longitudinal data over three measurement waves. Participants were 2,313 Japanese emerging adults enrolled in higher education (70.95% women; M[subscript age] = 20.43). The cross-lagged panel analysis and random-intercept cross-lagged panel analysis were used to estimate associations at both between- and within-person levels. Results indicated that commitment making negatively predicted negative identity elements, whereas identification with commitment positively predicted positive identity elements. Meanwhile, positive identity elements positively predicted identification with commitment only for participants with low levels of negative identity elements, while negative identity elements negatively predicted commitment making and identification with commitment. These associations were found only at the between-person level. The findings highlight that emerging adults develop identities through close interactions in which they engage in identity exploration and commitment processes, as well as construct identity content valences. Developmental sequences of identity, along with their sociocultural contexts and practical implications, are discussed.