Hendricks is primarily remembered as the co-composer of numerous soft-R&B songs of the 1950s, many in collaboration with Clyde Otis and Brook Benton, and as an accomplished arranger.
His versatility allowed him to write in various styles, from big band swing for Count Basie, through blues ballads for Dinah Washington and Sarah Vaughan, R&B-influenced pop for Benton and country and western numbers for Nat King Cole and Al Martino, to early soul for Aretha Franklin.
Hendricks married Mae Etta Bean of North Vernon, Indiana, a classmate studying to become an elementary school teacher.
Hendricks contributed a song, "Marching Through Berlin" that was sung by Ethel Merman in the 1943 wartime movie, Stage Door Canteen.
[4] During this period, he became acquainted with Emma Clinton, a native of Texas, who worked for Jane Blaffer Owen, heir to the Humble Oil fortune (now known as Exxon-Mobil).
His arrangements for her produced one minor US hit, "Smooth Operator", written by Otis with Murray Stein and some takes on older songs, such as "My Ideal", "I Should Care", Irving Berlin's "Maybe It's Because I Love You Too Much" and versions of Mack Gordon and Harry Revel's "Never in a Million Years" and Charlie Chaplin's "Eternally".
The result was a worldwide hit and Hendricks was asked to submit arrangements for a full album in a similar country and western vein.
When that brought more success, Hendricks arranged a follow-up Cole-meets-country album, Dear Lonely Hearts, whose title track became another singles chart hit.
Among other stars with whom Hendricks worked were big band leaders Jimmie Lunceford and Sy Oliver, Ivory Joe Hunter, Carmen McRae and Timi Yuro.
When Al Martino, whose sub-operatic singing style had gone out of fashion in the early 1960s, wanted to develop a more understated vocal technique, Nat King Cole recommended that he contact Hendricks for help.
Martino duly got his desired new sound and, to go with it, his biggest hit for years: a Hendricks-arranged reworking of the country song "I Love You Because", which got to number 3 on the Billboard pop chart in 1963.
According to author David Leander Williams, "The name Belford Hendricks must go down in history as the greatest arranger of rhythm-and-blues hits of all times".