Design is transitioning modalities, from participation to deep engagement, creating active citizen(s). Authors define, communicate, and navigate post-participatory sustainable design, (interviewing 50+ project leaders), catalysing sustainable activities. Engaging Design, enables creative individuals, communities & collective action(s) to craft/design synergies: motivated by mutual respect, designing ‘with’ not for, and shifts understandings’ of public engagement, transcending disciplines, providing sustainable value. Analysis and insights, yield recipes to cultivate sustainable active and Ecological citizen(s).