The COVID-19 pandemic exposed a gap in the preparation for virtual instruction and an effective use of technology. As teachers used technology and digital resources, perhaps unfamiliar to them, in response to the pandemic, there became an apparent need to determine what technology-related professional development, if any, teachers were provided for virtual instruction. The purpose of this qualitative study was to examine the perspectives and experiences of secondary mathematics teachers engaging in professional development in response to virtual instruction. The study also explored what digital resources were used to enhance student-centered instruction, and the pedagogical challenges and opportunities teachers experienced as a result of professional development that addressed these digital resources. Phenomenological methodology was used to gather data through semi-structured interviews with 10 secondary mathematics teachers with teaching experience prior to the pandemic. Findings evolved into three key takeaways that emerged from the data to answer the research questions with considerations for the following: (a) student-centered digital resources and pedagogical challenges and opportunities in response to the COVID-19 pandemic; (b) characteristics of desired, effective, and meaningful professional development; and (c) knowledge of, communication about, access to, and availability of digital resources. Participants suggested that technology provides pedagogical opportunities that may enhance learning with personalized experiences when technology is appropriately introduced with and supported by effective professional development. Participants explained the importance of learning lessons from the pandemic to inform future instruction. Schools should pay close attention to the experiences of teachers as they describe these personal lessons. [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.]