Leroy was born in Rayne, Louisiana. "Happy Fats" began his career that spanned more than 50 years at the early age of 17. His first performances were with Amedee Breaux and Joe Falcon. In 1935, one of his dreams came true as he formed his very own band, " The Rayne Bo ramblers," which starred the talents of "Happy Fats", Eric Arceneaux, and other great musicians. He played regularly at the OST Club in Rayne. In 1937, he played alongside Doc Guidry, and "Uncle Ambrose" Thibodeaux. Other associates were Luderin Darbonne, "Pee Wee" Broussard, "Pappa Caro" Lamperez, Rex Champagne, and Crawford J. Vincent.

He was invited and spoke on many radio stations including: KANE, KEUN, KUOH, KROF, and others. "Happy," being a self-taught musician, assisted and encouraged many aspiring musicians in making a name for themselves. His many recordings were played on radio stations in his beloved Louisiana, of course, but also national and international stations.

Some of his more memorable recordings consisted of "Colinda," "La Viewx De Accordion," "Mon Bon Vieux Mari" and "Dear Mr. President," for which he received a Silver record. "Happy" was honored time and time again throughout his career. Some of these recognitions included having November 9, 1980 named by Gov. Edwin Edwards as "Happy Fats" LeBlanc Day, presiding as Grand Marshal of the Rayne Frog Festival, having the "Dejeuner de boucherie" dedicating that year to "Happy" and his "Rayne Bo Ramblers," appearing many times on local news station, and on what was to be his final birthday. Family and friends for his long and successful career as an accordionist, singer and composer gave two hugh celebrations to him. He recorded music for the likes of RCA, Victor, Decca, Fais-Do-Do, Bella, and Cajun Classics.

Putting aside the fact that Leroy LeBlanc was an excellent musician, we can focus on the more important issue. He was married to Della and had three children, Carrie, Jimmie, and Molly, 17 grandchildren and 19 great grandchildren. He was a family man who, much like his name, brought "Happy"ness to those around him. He devoted many performances to raise money for charitable causes and was an active member of his Catholic faith.

He was diagnosed with diabetes and became ill in his last years, but his spirit remained the same. On Tuesday, February 23, 1988, Leroy "Happy Fats" LeBlanc was called home. The entire Cajun Community felt his death. Nearly every newspaper included information of his death and life long achievements; even the national publication USA TODAY had a paragraph on "Happy."