The purpose of this study was to investigate the role of period of incarceration, criminal friend index (a retrospective measure intended to quantify criminal associations before 1st incarceration), and 4 psychopathy factors (interpersonal manipulation, callous affect, erratic lifestyle, and antisocial behavior) in criminal social identity (CSI) while controlling for age and gender. Participants were a sample of 501 incarcerated offenders (male n = 293; female n = 208) from 3 prisons located in Pennsylvania State. Moderated regression analyses indicated no significant direct association between period of incarceration and CSI or between criminal friend index and Measure of Criminal Social Identity (MCSI). However, a significant moderating effect of interpersonal manipulation on the relationship between period of incarceration and MCSI was observed. Period of incarceration was significantly positively correlated with MCSI (particularly with the in-group ties subscale) for only those offenders who scored high (1 SD above the mean) on interpersonal manipulation and significantly negatively correlated for those who scored low (1 SD below the mean) on interpersonal manipulation. Also, criminal friend index was positively significantly associated with in-group ties for high levels (1 SD above the mean) of callous affect. The main findings provide evidence for the claim that prisoners are likely to simulate changes in identity through the formation of bonds with other offenders and that this can be achieved using interpersonal manipulation skills.