Ernie Leaner, saxophonist Gene Ammons and George Leaner. The Leaners’ One-derful! record label produced a number of R&B stars, whose work is now being reissued along with ”Big Boy” by the one that got away back in 1967, the Jackson 5. (Leaner family photo)

One day in July 1967 on Chicago’s Near South Side, a group of unknown brothers from Gary, Ind., stepped into a professional recording studio for the first time and taped a song called “Big Boy.” Their father, Joe Jackson, would have been familiar with this Michigan Avenue record company, One-derful!, established by brothers George and Ernie Leaner. Within two years of that summer, the world would know that musical family as the Jackson 5.

“Michael Jackson, even then, was inquisitive,” says R&B singer Otis Clay, who also recorded at One-derful! “He’d follow you around all day asking you questions.”

The Leaners didn’t end up releasing “Big Boy,” and, for decades, few could even attest to the recording’s existence. And, of course, the Jacksons’ subsequent success overshadowed that of their first producers. But, as a new compilation proves, the Leaners weren’t just a footnote to musical history.

The first volume of “The One-derful! Collection,” released late last month by Secret Stash Records, includes several of the old label’s releases, and its liner notes document its history, including the rediscovery of “Big Boy” (the Jacksons’ 45 is available with one of the installments in Secret Stash’s full subscription series).

The Leaners entered the record business almost by happenstance. In the 1940s, they both worked at their brother-in-law’s Chicago record store. A few years later, George and Ernie moved into record distribution, forming United Record Distributors and releasing jazz, gospel and soul singles and albums across the Midwest. It wasn’t until 1962, however, that they launched One-derful! to produce R&B.

A Sept. 15, 1972, photo of The Jackson 5 performing during the “Sonny and Cher Comedy Hour” in Los Angeles. (AP)

When the Leaners set up shop at 1827-29 S. Michigan Ave., they were joining a burgeoning industry on a street then known as Record Row. Chess, with its celebrated blues catalogue, may be the most famous today. The popular record companies Vee-Jay and Brunswick were a few blocks north and, like One-derful!, had African American executives. (This was at a time when Ebony magazine had editorialized that a supposed lack of black entrepreneurs was “the one weak link in the strong chain of Negro achievement.”)

The Leaners’ productions signaled a new sound for urban black youths. But both George and Ernie were born in Mississippi, so their label also connected to earlier generations of black migrants through their uncle Al Benson, an influential DJ in Mississippi.

The Leaners also nurtured younger black singers, such as Clay, who had moved to Chicago from the rural South, and opened their doors to local performers, such as Beverly Shaffer and Alvin Cash.

“George Leaner would talk to me about life,” Clay recalls. “We would sit around his office and talk for hours. Somehow, I became his son.”

The Leaners’ community engagement went beyond music, with George raising money for civil rights demonstrators and Ernie working with the Chicago Urban League.

One-derful! had a few hits, including the Five Du-Tones’ energetic dance single “Shake a Tail Feather.” The brothers also owned imprints that specialized in R&B, blues, teen-oriented tunes, early funk and gospel. (Secret Stash is reissuing those subsidiaries’ 45s through 2015.) The Leaner sound could be described as stripped-down instrumental arrangements associated with the South and upbeat rhythms associated with the Midwest.

“Since Ernie and George were distributing records through United,” says Will Gilbert of Secret Stash, “they would get records from labels outside of Chicago, and so they were on the pulse of what was happening. Combined with their own Mississippi roots, some songs sound like Memphis and some sound like Motown. It’s a hard soul sound.”

Memories of the time Joe Jackson brought his sons to One-derful! have long since faded. The “Big Boy” tape wasn’t unearthed until 2009, after studio guitarist Larry Blasingaine recalled those sessions and mentioned them to a journalist who was writing about the Jacksons’ early years. The Leaner family found the recording, but their work had just begun.

“We were standing there, we had this tape, but nothing to play it on,” says Ernie’s 52-year-old son, Eric. “I tried to find experts in the field who could bring old tape to life, because I didn’t want to ruin history. I found Steve Puntolillo at SoniCraft on the Internet, and a few days later, I’m listening to 8-year-old Michael Jackson singing this song.”

It’s not clear why the Leaners decided not to release the single (the Jacksons rerecorded the song with Steeltown Records the following year, which led to their signing with Motown). It might have had something to do with George Leaner’s retirement in 1968 (Ernie kept the business going for a couple of years and then opened a chain of record stores in the 1970s). Eric Leaner, who maintains the brothers’ archives, learned about his family history on fishing trips with his uncle, who died in 1983. His father, who also told a slew of dinner-table anecdotes, died in 1990.

“My dad was very charismatic, and my uncle was very meticulous,” Leaner says. “I saw the different roles. But I also learned a lot through meeting people, and 99 percent of them said, ‘Had it not been for your dad and your uncle, I would not be where I am today.’ ”

Today, the Leaners’ studio is a dental office in the shadow of high-rise condos, with nary a clue to its artistic past. The same can be said for the rest of Record Row — even Chess, which is open only sporadically for tours. Still, the music that the Leaner brothers and their colleagues produced has endured. And Eric Leaner hopes that the One-derful! reissue will inspire his family’s younger members.

“I’m trying to get my sons to understand that they come from a very, very prestigious family of strong black men who had an entrepreneurial spirit,” he says. “I try to instill that in them and motivate them every day to continue to push the name forward.”

Cohen is a freelance writer.