= 918) were conducted. Study 1 found through a field study that frequent smartphone use increases nostalgia. Studies 2 and 3 found through 14-day tracking and a laboratory experiment that frequent smartphone use decreased people's sense of control and then triggered nostalgia. Furthermore, nostalgia could enhance the low sense of control, and it worked by increasing self-esteem (Studies 4 and 5). The findings show the negative impact of frequent smartphone use, and nostalgia is an effective way to remedy it without preventing people from using smartphones.