Teachers in the United States are experiencing challenges linked to the increasing number of immigrant students entering schools. Los Angeles County Charter schools are among the country's most diverse, with many immigrant students. Although first-generation and immigrant students' education barriers and teacher challenges are documented, little is known about teachers' experiences with newcomer students, a particularly vulnerable group. This phenomenological study explored charter high school teachers' lived experiences concerning their teaching challenges and perspectives on the barriers for first-generation/newcomer immigrant students, their descriptions of the strategies and practices used, and their perceptions of the support they receive. Twelve teachers from 3 high schools participated in one-on-one interviews with 10 questions. Virtual interviews were recorded, transcribed, and analyzed using coding and thematic analysis, emphasizing a phenomenological multiple perspectives approach. Bandura's self-efficacy theory was used to interpret the findings for three research questions and the related literature. Three themes were developed: (a) meeting the learners where they are to understand their challenges and barriers to learning; (b) purposefully, responsibly, resiliently, and collaboratively building learning strategies and reflecting a multicultural school climate; (c) recognizing the benefits and needs to improve professional development: the champions and the discontented. Three conclusions were found: (a) teachers need more training on overcoming barriers and challenges to teaching first-generation students, (b) teachers need support in using teaching strategies and engaging first-generation students, and (c) teachers need more time for collaboration. Recommendations for teachers included (a) finding ways to build their resiliency and self-efficacy, (b) taking responsibility for their classrooms and creating a positive environment, (c) showing empathy toward newcomers, (d) embracing multicultural learning, (e) collaborating, and (f) using multiple and multimodal learning strategies. Among the several recommendations for administrators and site leaders were (a) communicating with the families, (b) creating teacher professional development, (c) dedicating time for collaboration, and (d) sharing a clear vision for a multicultural climate and educational environment. The recommendations for policy and practice were (a) to have teachers discuss concerns for first- generation immigrant students, (b) to provide dedicated time to address newcomers' needs, and (c) to provide strategies and support for teaching newcomer students. [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/en-US/products/dissertations/individuals.shtml.]