As a result of increasing urbanization, the need for sustainable housing, e.g., tall (over eight-story) timber apartments, is increasing in Finland. Leveraging the experience of key Finnish professionals plays a significant role in the transition and expansion of sustainable timber housing as an essential part of the forest-based bioeconomy. This interview-based study will serve to fill a gap by examining the views of key professionals with experience in tall timber residential construction, using Finland as a case study. The 21 interviews primarily highlighted that: (1) the construction cost was the most important parameter affecting the architectural and structural design; (2) the most critical consideration influencing the overall design was reported to be the structural system selection and structural design, followed by city planning and client control; (3) key professionals assessed the building’s form and the main dimensions of the building’s mass as the most significant parameters affected by timber construction; (4) the main structural considerations that needed to be developed for tall timber housing were the bracing solutions and fittings, the structures of the intermediate floors, and load-bearing vertical/partition structures; (5) construction preconceptions, the lack of cost-competitiveness, and the lack of construction expertise/actors were considered to be major obstacles; (6) the most important parameters for the future of tall timber apartment buildings were reported to be education, timber construction marketing and public awareness, land delivery conditions, the unification of public administration, and financial support; (7) tall timber building design was reported to be a complex subject that requires close collaboration, especially between the architect, the structural designer and the wood supplier. This paper will help us to understand the boundary conditions affecting the design, the development needs in solutions, the importance of design parameters, the design parameters affected by timber construction, and the prospects, measures and obstacles to tall timber apartments from the perspectives of key Finnish professionals, thereby aiding the sound planning and development of tall timber housing projects.