A vast amount of Latina/o/x students enroll in US public schools with the potential to become bilingual in English and Spanish. However, this potential is often dismissed, ignored, and their Spanish is perceived as a problem to be overcome. Despite this, some Latina/o/x bilingual students decide to become Spanish as a Heritage Language (SHL) educators. My dissertation is a two-phase qualitative study drawing from Latino Critical Race Theory (LatCrit) and Chicana Feminist Theory to inform its theoretical framework and methodology. Participants for the first phase consisted of 11 Spanish as a Heritage Language (SHL) high school teachers who are Spanish heritage speakers themselves. The study captured participants' testimonios, in which they reflected on their language experiences across the PreK-16 educational pipeline and shared how these experiences presently inform their teaching practices in their SHL classrooms. Testimonios were collected via a semi-structured interview and a written sociolinguistic autobiography. Preliminary findings were co-constructed with participants via a platica, disrupting the Eurocentric practice of the researcher positioned as the sole interpreter and creator of knowledge. The findings for the first phase of this dissertation study informed the design of the second phase, which consists of a Critical Action Research (CAR) study. Findings revealed that participants experienced linguistic discrimination at different points throughout their educational trajectories. Participants reflected on being positioned as lacking English language skills during elementary school, and during their pre-service teacher education, being criticized for their non-standard Spanish language practices. Because of these negative experiences, participants practiced asset-based pedagogies in their own classrooms; yet, some still prioritized the acquisition of standard Spanish. Findings for the second phase revealed that the CAR project served as (1) a tool for educators to develop critical consciousness, (2) an affinity space that provided ongoing critical professional development that disrupted the deficit framings of the cultural, linguistic, and historical funds of knowledge of U.S. Latina/o/x student communities, and (3) a safe space to build community among SHL educators across the Chicagoland area. The results of this study expand the scarce knowledge base in both Bilingual Education and SHL about the experiences of Latina/o/x students across the PreK-16 educational pipeline and offers implications for changes in Spanish language teacher preparation programs that are centered around humanizing and socially just pedagogies. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]