He signed with TK Records in Miami. In 1978, after songs for his first album were recorded, executives told Caldwell they enjoyed the album, but thought it was lacking a hit. Caldwell returned to the studio for two days and wrote “What You Won’t Do for Love”. TK was mainly an R&B label popular among African American listeners. Executives at the label wanted to conceal the fact that Caldwell was white, so they kept his face off the album cover. When he toured with Natalie Cole to support the album, most of the audience was black and many were surprised that Caldwell was white.

Caldwell’s debut album was followed by Cat in the Hat (1980) and Carry On (1982). For the latter album, Caldwell played all the instruments, was the producer and helped with arranging and mixing. In 1983, Caldwell released August Moon only in Japan. It was released in the United States in the 1990s.

Caldwell is popular in Japan, where he was nicknamed “Mister AOR.” In Japan, the acronym “AOR” (AOR short for “Adult Oriented Rock”) is used to describe the style commonly called Adult Contemporary in the United States. In 1992, he received Japan’s equivalent of a Grammy Award for Best International Artist. Caldwell said in a 2007 interview, “At first it was awesome, the whole “big in Japan” experience, but then it was not so fun.”

“What You Won’t Do for Love” reached the top ten on the Billboard magazine Pop (No. 9) R&B (No. 6), and Adult Contemporary (No. 10) charts. The song has been covered, remade and sampled many times. Caldwell remade it in 1998. It was covered by Go West, Phyllis Hyman, and Boyz II Men and was sampled by Tupac Shakur. It was covered by Elliott Yamin during the fifth season of American Idol in 2006. The 1980 track “Open Your Eyes” was sampled by J Dilla on Common’s “The Light” from his 2000 album “Like Water For Chocolate”.

On Blue Condition (1996), Caldwell turned from R&B to recording big band arrangements of songs from the Great American Songbook, particularly those sung by Frank Sinatra. He also portrayed Sinatra in tributes to the Rat Pack in Las Vegas. He continued to sing standards on Come Rain or Come Shine (1999), The Consummate Bobby Caldwell (2010) and After Dark (2014). In 2015, he collaborated with record producer Jack Splash on the album Cool Uncle.