This study investigated the influence of acquired L1 writing skills on exophonic writings of students (N = 147) from diverse majors, who visited an English writing center for assistance. Affective differences revealed students with L1 writing tutelage (WL1) had lower avoidance behavior and higher extrinsic motivation and writing self-efficacy. Self-perceived L2 writing ability was found to be a principal factor for WL1. Writing self-efficacy appeared essential for students without L1 writing tutelage (WOL1). Regression analysis found learner self-beliefs and somatic anxiety (negative) influenced self-perceived L2 writing ability for WL1, and holistic self-beliefs on English writing (HSE) and cognitive ability (negative) for WOL1. Acquired L1 writing skills did not tangibly influence L2 performance. No large impact factors were found for WL1, but HSE and attitudes & reaction (negative) impacted WOL1 performance. Implications such as performance may not be a main concern among exophonic writers, and the need for English writing centers in non-L1 (English) countries are discussed.