The purpose of this study was to identify the strategies, practices, and leadership skills utilized by California superintendents in implementing 21st-century skills in their respective districts. A mixed-methods design was used, combining qualitative and quantitative analysis. Quantitative data from 37 California superintendents were collected via an online survey and two currently employed superintendents in southern California participated in face-to-face interviews. Purposeful sampling was used to select 2 superintendents who met specific criteria to provide focused and meaningful data. Interview and survey data were reviewed and analyzed to identify commonalities, themes, and patterns in the responses. The findings revealed that superintendents had a shared understanding and definition of 21st-century skills aligned to Wagner's definition: critical thinking, communication, creativity, collaboration, and the use of technology. Analysis of data identified strategic planning, professional development, and a focus on curriculum design as practices used by superintendents to implement 21st-century skills. Teachers, school-level administrators, and district personnel were identified as key stakeholders needed for superintendents to implement 21st-century skills successfully in their districts. The use of data and multiple measures emerged as a central theme in evaluating the effectiveness of implementing 21st-century skills. Evidence drawn from the findings provide important lessons for educational leaders who plan to implement 21st-century skills in their district, school, or organization. The findings revealed that superintendents can address 21st-century learning needs using a variety of leadership strategies and methods. The study contributes to the body of scholarly literature on superintendent leadership. Because the role of the superintendent is multifaceted, superintendents must possess a wide and varied skill set. [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.]