This dissertation explores the ways in which media artworks depict agency and convey life-like qualities. This exploration is centered around the design and implementation of two interactive media artworks, HIVE (2016--2018) and Cacophonic Choir (2019--2020), and makes use of a novel conceptual framework grounded in an approach to media arts practice that uses the notion of agency as a lens for examining and creating artworks. Starting with an inquiry into novel agent-based art practices that neither feature robotic nor virtual agents, the dissertation reevaluates the notion of agency in artistic contexts in light of the relatively recent establishment of sonic interaction design as a field in its own right and the renewed emphasis on materiality as the result of rapidly evolving design and fabrication technologies. To this end, I introduce Sonically Actuated Spatial (Sono-spatial) Agent practice as an area of artistic practice that fuses digitally designed and fabricated artifacts, sonic expressions, and interactive behaviors in order to create ‘perceived’ life-like systems. In summary, this dissertation aims to expand upon the theoretical and conceptual underpinnings of interactive media arts via the products of my artistic practice, as well as theoretical discussions, design methods, principles, and strategies, all of which are distilled from this practice.