This chapter focuses on the active employee and reviews the following proactive performance concepts: employee proactivity, personal initiative, job crafting, and idiosyncratic deals (i-deals). The discussion of employee proactivity will introduce the general concept of proactivity at work. Personal initiative is included because this concept has been used in many studies investigating the proactive employee. Job crafting is reviewed as an example of how employees proactively shape their own jobs, whereas i-deals are discussed as an example of how employees may take the initiative to negotiate specialized employment conditions with the employer. The chapter discusses link between the proactive behaviors and well-being and performance. Although the literature on proactive behavior at work is diverse and spread among different fields, various researchers have successfully aimed to integrate this literature. Regarding the proactive constructs, there are indeed some signs that negative relationships with performance or well-being exist.