The study aims to widen understanding of English idiom usage in movies and raise awareness of the importance of idioms by presenting the connections between idioms and social factors. The series “How I Met Your Mother, Season 1” is chosen to be a source due to its modern plot and simple idiom usage. Moreover, this study provides idiom characteristics and types according to their usages and unique properties. Combining with the theory of speech act types, it is also expected to reveal intentions of idiom usages by characters in the series. To perform this qualitative research, 90 idioms were collected manually from the script of the series (11 episodes) by using observation and note taking techniques. Then, the dialogue with idioms were cut out and arranged in the designed analysis form. The analysis started by seeking the idioms’ actual meanings and origins through American dictionaries. After that, their types of idioms and types of speech acts were also determined following Fernando (1996) and Searle (1969) in order to reveal each idiom characteristic and reasons of their usages. The last step was to give an explanation to clarify the scene. The results show that compositeness was the most used idiom type in this series with the total of 67 idioms or 74% due to its easy-to-use feature. Supported by the types of speech acts, representative was found to be the most used speech act type which commonly occurs through an explanation, an advice or a complaint.