This paper is the executive summary of the portfolio of the author toward the award of Engineering Doctorate of the Warwick University. The title of the portfolio is the same as the title of this paper, which serves as a tool to integrate the works of the author in the whole portfolio. There are ten other papers in the portfolio besides this one. The development and implementation of the author's model of Strategic Change Management (SCM) in a power supply manufacturing company in Hong Kong leading to Agility (AG) is presented in the paper. SCM developed by the author is a comprehensive and practical model that a company can use to improve various aspects of its business. The author has demonstrated this in the areas of Total Quality Management and IS09000 implementation, technology innovation, supply chain management, renovation of information systems, etc. Three mini research projects are included in the portfolio, including the development of a What-if prototype to tackle a common problem in manufacturing resources planning, the design of power supply products for mass customization, and an empirical study on the factor structures and correlations of employee job satisfaction (SAT), organisation excellence (EX) and agility (AG). The SCM model starts with creating the culture for change, which the author sees as the role for the top management of the organisation. The author presents his experience to create such culture when he was parachuted into his organisation as the chief executive. The second step of SCM is analysing the system. A comprehensive qualitative analysis of the economical, social and cultural environment of the company as well as the market forces is given. The step that follows is the implementation of changes, which is a cycle of setting priority, organising, performance measurement, rewarding winners and reinforcement. Practical approaches to tackle the changes in various stages of the cycle are presented. SCM has helped in transforming the company toward agility, and the stage of agility is named Agility Chain by the author. The result of such transformation is also evaluated from the angles of operations performance, financial performance, stock price appreciation, and the change in market perception. The empirical study of employees perception on SAT, EX and AG indicates strong correlations among the three factor structures, and also indicates that the company is moving toward agility under the author's strategic change management.