Meadows was born Jayne Meadows Cotter in Wu-ch'ang (now Wuchang), China, to Episcopal missionary parents, the Rev. Francis James Meadows Cotter, and his wife, Ida Miller. The family later returned to their home in Connecticut, United States.

Meadows' most famous movies include: Song of the Thin Man (with William Powell and Myrna Loy), David and Bathsheba (with Gregory Peck, Susan Hayward and Raymond Massey), Lady in the Lake (with Robert Montgomery and Audrey Totter), and City Slickers (as the voice of Billy Crystal's oversolicitous mother).

Meadows was a regular panelist on the original version of I've Got a Secret and an occasional panelist on What's My Line?, the latter alongside husband Steve Allen. During the early days of the burgeoning live entertainment scene in Las Vegas, the Allens occasionally worked together as an act.

Meadows was the older sister of Audrey Meadows, whom she survives, as well as having had two brothers who are also deceased.

She was married to Steve Allen from 1954 until his death in 2000, by whom she had one son, and several step-children.