Social movement research has long been part of studying how framing processes and emotional involvement influence participation in collective action. However, little is known about how these micro-level mechanisms affect individual mobilization outcomes in online social movement campaigns. In this study, I first explore how social movement organizations’ framing, through the use of language, symbols, and slogans, characterizes movement members’ discourse in social media and the extent to which the movement’s dominant framing becomes hegemonic during online mobilization. Then, I investigate how movement members’ adoption of the movement’s dominant framing in the online discourse and their level of emotional involvement in the framing process influence individual fundraising outcomes during a health-related campaign on Twitter. By combining automated text analysis, the use of a plagiarism detector, network visualizations, and regression analysis, I find that almost one-third of the discourse that movement members generated on Twitter during the campaign aligns with the Movember Foundation’s dominant framing. However, the more movement members use the movement’s language, slogans, and frames in their tweets, the less they collected in donations. By contrast, the use of emotional language in framing processes was positively associated with the amount collected in donations. In this way, I show the importance of the authenticity of communication and emotions as important micro-mobilization dynamics related to individual participation in online social movement campaigns. This study contributes to research on social movements, organizations, media, and communication.