One of the mysteries of the English language finally explained.
1rare A performer whose name appears on the bottom line of the bill advertising a particular performance, venue, etc. (typically as the second or third most important act in the programme). Compare "top-liner", "headliner". Now rare.
2A person (typically a business executive, accountant, etc.) regarded as chiefly or only motivated by financial considerations, especially final profits. Also more generally: a person interested only in the overall outcome or essential facts of a situation.
Early 20th century; earliest use found in Era. From bottom line + -er.
bottom liner/ˌbɒtəm ˈlʌɪnə/
In this article we explore how to impress employers with a spot-on CV.