The number of people who complain of sleep disturbances is steadily increasing. An understanding of sleep-related factors is required to address sleep problems. This survey study investigated the sleep habits and sleeping symptoms relating to the comfort and support characteristics of pillows and the relationship between sleep quality and pillow design factors. The study utilized data from 332 participating Korean adults aged 20-76 years (mean age ± SD: males, 40.4 ± 15.2; females, 42.9 ± 15.4). We developed a questionnaire that evaluated sleep habits (sleep duration, bedtime, wake-up time and sleeping position); sleeping symptoms (snoring or coughing, breathing and sleepiness during waking hours) based on the Korean version of the Pittsburgh Sleep Quality Index (PSQI-K) questionnaire; and pillow-related factors (support, comfort, fatigue, height and shape) from existing pillow studies. The average sleep duration was 6.8 h, with more than half (52%) of participants sleeping in the supine position. The overall score for sleep quality was considered poor (4.84 points on a seven-point Likert scale), with some degree of sleepiness during waking hours (4.4 points on a seven-point Likert scale). Females went to bed earlier than males and were more likely to sleep in the lateral position compared to males. The number of toss and turn or waking events during sleep increased with age, and older individuals went to sleep earlier and woke up earlier. Among the symptoms of fatigue, pain, discomfort with changing position, snoring, coughing and breathing discomfort, participants reported their highest levels of discomfort due to sleepiness after waking, and they experienced the least head pain. Participants who used a regular-type pillow had poorer satisfaction on multiple comfort and support factors (support, comfort, height suitability, shape suitability) compared with those who used a functional-type pillow. Less head fatigue, less neck fatigue and less shoulder pain had significant effects on sleep quality. To reduce neck fatigue and shoulder pain, designers should consider the height for neck support in the lateral position. To reduce neck fatigue, it is desirable to use materials like latex or memory foam that provide neck support, which can improve sleep quality. The findings of this study contribute to a better understanding of sleep habits and characteristics of pillow comfort and provide practical guidelines for better pillow designs.