This study examines and analyzes the impact and support of preservice teachers on 74 featured P-5 students' learning outcomes during units of instruction in three practicum tiers in an early childhood education program. The quantitative results indicate a significant difference in the P-5 students' gains on the pre- and post-assessment for unit instruction. However, there is no significant difference in gains between the three tiers, student gender, social economic status, grade levels, and subjects taught. The qualitative results reveal that the preservice teachers effectively support their P-5 students' learning through providing accommodations and modifications, monitoring student progress, and offering recommendations to family for support--strategies which lead to significant impact on the P-5 students' achievement. Recommendations include improving preservice teachers' ability to analyze, interpret, and present data, and collecting data systematically in regards to preservice teachers' impact on their students learning during their practicum experiences.