The organizational location of leaders who are middle managers necessitates sensemaking of ambiguous information. Through semi-structured interviews and a five-question survey, this mixed-methods study explored the sensemaking practices of 20 middle managers who work in an organizationally complex environment. Three research questions were investigated: (a) What strategies do middle managers in a large, urban school district use to make sense of the critical aspects of their job? (b) How do these leaders’ sensemaking strategies influence actions taken on critical aspects of their job? and (c) What relationships exist between sensemaking strategies and personal or professional characteristics? The majority of participants reported undefined tasks as originating from the top-down, with 13 sensemaking strategies emerging from the interviews. While participants did report sensemaking independently, social sensemaking practices were reported over four times as often. A Fisher’s exact test was used to determine if there was a significant association between five personal or professional characteristics and each of the 13 sensemaking strategies. The test demonstrated seven significant relationships associated with experience working in a K–12 school, gender, race, and tenure in the role. Four major findings emerged: (a) themes in sensemaking practices imply a connection with the predominantly top-down origination of undefined tasks; (b) themes in sensemaking strategies are responsive to a horizontally complex organizational structure; (c) the reliance on relationships and institutional knowledge compensate for the absence of knowledge management systems in the organization; and (d) sensemaking is an inherently social process. These findings pointed to three recommendations for how large, urban school districts can create conducive conditions for middle managers to make sense of undefined tasks. The recommendations included developing a full-year onboarding process for new middle managers, systematizing tools and processes that manage knowledge across the organization, and creating routines that promote knowledge sharing and social sensemaking.