As gentrifying dual language (DL) schools in the United States increasingly attract students with linguistic, racial, and socioeconomic privilege, a key consideration is whether these schools are intentionally supporting the specific needs and assets of emergent bilingual (EB) students from Latinx families. This dissertation of practice examined how an asset-based early literacy intervention in a first grade English DL classroom could recenter EB students through both structured literacy instruction and parent partnership, using a funds of knowledge framework. The 11-week Student Intervention explored how a teacher could actively build upon EB students' Spanish language and literacy competencies within small-group English reading instruction at the beginning of their formal bilingual education. Quantitative findings showed that explicitly grounding early English reading instruction in the transfer and non-transfer of Spanish literacy skills supported students' progress toward grade-level expectations for English decoding and letter sound knowledge. The parallel Parent Intervention centered parent voices through qualitative interviews. Findings indicated that Spanish-speaking families expressed unique capacities to support biliteracy learning grounded in Science of Reading-based practices. The implications from this study direct DL educators to deepen collaboration towards biliteracy by continuing to explore and incorporate elements of cross-linguistic transfer and families' funds of knowledge. Recommendations for student instruction, teacher professional development, family partnership, and research, within the context of early biliteracy, are discussed. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]