Effective communication between providers and patients with serious illness is critical to ensure that treatment is aligned with patient goals. We developed and tested an implementation strategy for incorporating the previously developed Serious Illness Conversation Guide (SICG), a clinician script, into hematology-oncology fellowship training at a single US academic medical center. Between December 2017 and April 2018, we trained 8 oncology fellows to use and document the SICG. The training included associated communication skills-such as handling emotion and headlining-over 7 didactic sessions. Implementation strategies included training 4 oncology faculty as coaches to re-enforce fellows’ skills and an electronic medical record template to document the SICG. We assessed effectiveness using 4 approaches: (1) SICG template use among fellows in the 12 months following training, (2) fellow confidence pre- and post-intervention via survey, (3) performance in 2 simulated patient encounters, and (4) semi-structured interviews after 12 months. Fellows successfully implemented the SICG in simulated patient encounters, though only 2 of 6 fellows documented any SICG in the clinical practice. Most fellows reported greater confidence in their communication after training. Thematic analysis of interviews revealed the following: (1) positive training experience, (2) improved patient preference elicitation, (3) selected SICG components used in a single encounter, (4) prioritize other clinical duties, (5) importance of emotion handling skills, (6) no faculty coaching receive outside training. Despite acquisition of communication skills, promoting new clinical behaviors remains challenging. More work is needed to identify which implementation strategies are required in this learner population.