Queen Esther, a trad jazz vocalist, strikes a pose at Ginny’s Supper Club in Harlem. Guerin Blask

About sixty years before car stereos filled New Yorkers’ public lives with music, early jazz bands kept us humming as we went about our day. The late 1910s and ’20s packed the city with players who entertained everywhere from nightclubs to afternoon tea dances to, occasionally, department stores. Their music was melodic but disarmingly complex, with a steady beat perfect for dancing. We now call this music traditional, or trad, jazz and hail brilliant players like Joe “King” Oliver, Jelly Roll Morton, and Sidney Bechet as the men who shaped the sound.

What we’ve forgotten, in large part, are the women whose work both on- and offstage was just as crucial. “I grieve for the ghosts who are still amongst us — the black women who changed the world with their musicianship, their sound, their way of performing,” says Queen Esther, a jazz vocalist who lives in Harlem. “How ironic that their powerful influence is everywhere in jazz, and hardly anyone knows who they are.”

A vocal purist who’s been performing trad jazz in New York and nationally for years, Queen Esther makes a point to include songs by pioneering women in her sets. Her next performance is for a particularly appreciative audience, at the Jazz Age Lawn Party, an annual celebration on Governors Island that takes place this weekend and again in August. “It’s real music written by real people that are playing real instruments and putting themselves into what they’re doing,” she says. “It takes a certain amount of style and technique and craft and intensity. [It’s] the DNA of absolutely everything that is American.”

Vocalists like Bessie Smith and Ma Rainey, whose songs Queen Esther sings, are part of that DNA. So is Alberta Hunter, who wrote Smith’s first hit, “Down-Hearted Blues.” A singer as well as a songwriter, Hunter got her start in 1917 at the Dreamland Ballroom in Chicago and spent the next few decades performing in nightclubs there, in New York, and across Europe.

The Dreamland is also where Lil Hardin, one of the most influential figures in early jazz, made her name. The wildly talented pianist, composer, bandleader, and singer was a sought-after musician in Chicago and played for King Oliver’s band through the early ’20s. She receded from the spotlight when she married Louis Armstrong in 1924, but she continued to shape the genre through the ’50s.

And it turned out she was most powerful from backstage. She’s widely credited with having shaped every aspect of Armstrong’s career, from writing songs to choosing his wardrobe. “I don’t think Louis Armstrong would have the place in American popular culture he has without Lil Hardin. Now, do you ever hear about her? Not much,” says Elizabeth Bougerol, the singer and frontwoman of the Hot Sardines, a New York–based trad jazz outfit. When the band plays Hardin’s composition “Struttin’ With Some Barbecue,” a song Armstrong made famous in 1927, Bougerol always mentions Hardin’s name from the stage. “I definitely love when we can spotlight a woman who an audience might not have heard of,” she says.

A similar obscurity encircles Irene Wilson, another pianist, arranger, and bandleader largely forgotten after she propped up the piano career of her husband, Teddy Wilson. According to Queen Esther, who considers her an inspiration, “She ups his technique, she’s the one who takes him from good to great, and then what happens? He gets the gig with Benny Goodman and she stays home and takes care of the kids.”

As hot jazz gave way to big band and, later, bebop, many of the best musicians — female or male — were lost to fading interest. But since the early Aughts, trad jazz has come back around, and music fans can now hear it every night of the week in New York, at nouveau speakeasies like the Back Room on the Lower East Side and restaurants like Radegast Hall & Biergarten in Williamsburg. Summer brings even more opportunities: In addition to the Jazz Age Lawn Party, there are trad jazz events at Midsummer Night Swing and SummerStage, where Bougerol and the Hot Sardines play June 25.

With that resurgence come fresh opportunities for recognition. Like many of their foremothers in the genre, the women of the trad jazz revival are often vocalists, a “canary” role that Bougerol loves but still sometimes finds limiting. “When we go on tour and [are] going through customs, they ask, ‘What do you do?’ [I say] ‘I’m a musician’ and they say, ‘Are you the singer?’ That reveals the assumption that if you’re a woman, you’re probably not a drummer, you’re probably not a saxophone player.” Bougerol is, of course, a singer, but she also writes songs, works on arrangements, and runs the Hot Sardines with her partner Evan Palazzo; her contributions start long before she puts on her sequin pants and steps in front of the microphone.

Others are working hard to make sure the names and stories of trad jazz stay alive and well. Bria Skonberg, a trumpet player and vocalist who will also play SummerStage this month, co-founded the New York Hot Jazz Festival in 2013. She’s since turned her focus to Hot Jazz Camp, an annual event during which she works with musicians to hone their sound and dig more deeply into the early jazz catalog; she takes care to introduce her students to both forgotten luminaries and current masters like trumpet player Ingrid Jensen.

And, although Skonberg is one of few female trad jazz instrumentalists in New York, she thinks there’s plenty of room to see more faces like hers in ensembles, as well as in the singer’s spotlight. “I’ve never been on a bandstand and felt that I had a lesser chance of making music because [of my gender],” she says. “It’s a good time to be a woman in jazz.”