The medium-term impact of emotional literacy support assistant (ELSA) intervention is unknown. Therefore, emotional literacy (EL) data were collected through intervention assessment records (IAR) and social and emotional support assessment (SESA) questionnaires from 18 children and young people (CYP) and 18 ELSAs and class teachers (CTs) jointly measuring the effect of a six-week intervention, employing a within-subjects design. Twelve primary schools, four secondary schools, one special school and one pupil referral unit (PRU) participated. A series of t-tests (95% CI) showed a significant positive impact on CYP's EL following six weeks of ELSA intervention with CYP, p < .001 (g = 0.57) and CT and ELSA perspective, p < 0.001, (g = 0.45), with no improvements for the control group. EL gains were maintained 10 weeks post intervention with CYP p < 0.001 (g = 0.57) and CT and ELSA perspective p < 0.001, (g = 0.35), thus providing tentative evidence for the impact of ELSA intervention in supporting CYP's EL that extends beyond a six-week interval time phase. Further research is suggested to build on the evidence base.