She began her career writing for "women's magazines" that produced romance novels as six-part serials. In 1935, she was described as the newest of the "highly paid" women romance writers by Time magazine. Her popularity was at its peak in the 1930s, and in 1936 she earned over $300,000 (approximately equivalent to $4 million in 2005). However in the 1950s she was still going strong, with earnings over $2 million, sales over 10 million in all editions, and "one of the handful of living novelists to complete a five-foot shelf." She continued writing novels until her death in 1978.

Many of her books were made into films. and in the early days of television, she hosted a weekly Saturday afternoon anthology series on ABC network, entitled "Faith Baldwin Romance Theater." From 1958 to 1965, she wrote a column that was published in Woman's Day magazine called "The Open Door." Her comments are often found in books of quotes and in web sites that offer quotes. When asked about her life philosophy, she responded that her belief was simple: "It is in God and His spirit in mankind. It is in man and his struggle. It is in the Golden Rule and in the valor of men, however ignoble their shortcomings."

In the 1960s, Faith Baldwin became familiar as one of the "guiding faculty members" of the Famous Writers School, a heavily advertised correspondence school that drew criticism for allegedly deceptive advertising. The "faculty" included Baldwin, Bennett Cerf, Bergen Evans, Bruce Catton, Mignon G. Eberhart, John Caples, J. D. Ratliff, Mark Wiseman, Max Shulman, Rudolf Flesch, Red Smith, Rod Serling. An inattentive reader could have mistakenly inferred from the ad copy that these writers personally reviewed and critiqued student work.

She died in 1978.