Joshua Brooks, an original member of the Washington DJ trio known as Spiritus Cheese, which helped transform WHFS-FM into a haven for underground rock and a respite from Top 40 blandness that pervaded the music scene, died Jan. 30 at a rehabilitation center in Frederick, Md. He was 73.

The cause was complications from lung cancer, said his son, Zachary Brooks.

WHFS began life in 1961 as a 2,300-watt station in Bethesda, Md., that beamed the string instrumentals of Mantovani, the serene pop of Patti Page and other easy-listening favorites. Some wags suggested that the station’s call letters, an acronym for Washington High Fidelity Stereo, stood for We Have Frank Sinatra.

General manager and part-owner Jake Einstein, an advertising salesman who came of age in the 1920s and ’30s, had not grown up a rock enthusiast but had instincts for profitable radio.

“Then a guy named Frank Richards came in one day wearing cutoffs and a leather vest, played me a tape of rock music from Los Angeles,” Einstein told The Washington Post in 1983, adding: “We were losing so much money that another couple of dollars couldn’t hurt, right? So we put him on. My God, the calls! I never knew we had an audience!”

He became convinced he could drive up ratings — a paltry 800 listeners a night — by changing to a more contemporary format. He was receptive when three young Bard College friends and aspiring DJs — Joshua Brooks, Sara Vass and Mark Gorbulew — walked into WHFS in July 1969 and proposed a free-form blues and rock program they wanted to call Spiritus Cheese. They also agreed to pay Einstein for the privilege, $160 for each segment, to run four consecutive Saturday nights.

“We had spent our years in college being stoned and listening to music, and we wanted to be able to continue that,” Mr. Brooks told The Post in 2005. “We just wanted to get the music out there and make enough money to sustain ourselves.”

Named after a defunct Manhattan cheese factory, Spiritus Cheese immediately drew a devoted following with its adventuresome playlists (the Who, Joe Cocker, Frank Zappa, Little Feat, Country Joe and the Fish, and Ten Years After).

Each program was exhaustively researched — giving it a “serious, almost academic tone,” Post art critic Paul Richard once wrote, noting that a segment devoted to Elvis Presley not only offered a playlist featuring the King, but also paid homage to those who had influenced him, such as the Delta blues master Arthur “Big Boy” Crudup.

Mr. Brooks, Vass and Gorbulew spent their days scouring local record stores, recruiting advertisers and interviewing musicians at clubs and festivals. They managed to get backstage at Woodstock that August, thanks to a musician friend of Mr. Brooks. “We had access to anybody we wanted,” he later told the Frederick News-Post, noting Jerry Garcia and Neil Young among the acts who agreed to interviews.

Washington had long been a musical backwater for rock, slow to adapt beyond the most mainstream tastes. Spiritus Cheese proved a radical awakening — “the first real progressive underground sound on the local airwaves,” said Joe Lee, the former owner of Joe’s Record Paradise in Montgomery County.

The group’s embrace of alternative rock and roll — “hippie music,” Lee said — quickly won WHFS a devoted following of students, musicians and other cultural tastemakers. It had a resounding impact on local record shops and clubs, and its playlists ultimately “bled into other stations.”

“Josh,” he said, “had as much impact on radio in the D.C. area as anyone ever did. They were the only people in town with interviews from Woodstock, and suddenly everyone was paying attention. Boom! Everyone wanted to advertise with them.”

As the ratings advanced — 32,700 each weeknight, according to one research study at the time — Spiritus Cheese began airing six times a week, with each member (now sharing $100 a week from Einstein) having a designated night.

Their glory as a trio was short-lived. In 1970, Vass broadcast a segment of the Firesign Theatre satire troupe that included explicit language and a reference to masturbation. At least one listener wrote to management citing federal communications law regarding obscenities.

Vass was suspended for a month and briefly returned to the air before an advertiser expressed his displeasure with female DJs. On his next show, Gorbulew proceeded to criticize management for its “male chauvinism.” Both were soon gone.

Mr. Brooks remained on the air for several more years, helping to popularize local groups such as Root Boy Slim and the Sex Change Band, and was credited with broadcasting some of the more vibrant pop music of the era.

The WHFS lineup also included Einstein’s sons David and Damian and DJs Adele Abrams, “Bob Here” Showacre, Donald “Cerphe” Colwell and Jonathan “Weasel” Gilbert — all of whom steered clear of Top 40 in favor of rock, blues, jazz and reggae. The DJs gave early airtime to then-obscure musicians such as Bruce Springsteen and Elvis Costello.

Mr. Brooks left the DJ booth in the late 1970s, saying it had become hard to earn a living spinning records. In 2010, he received a citation of special appreciation from the Washington Area Music Association, noting his contributions to WHFS, which eventually changed hands and long ago ceased its distinctive programming.

Henry Stanford Brooks was born in Manhattan on Feb. 9, 1946, and grew up in Hastings-on-Hudson, N.Y. His father, Thomas, was a stockbroker. His mother, Anita, was an author and later married Max Abramovitz, an architect who designed Lincoln Center’s Avery Fisher Hall.

The younger Brooks graduated in 1964 from the private Solebury School in New Hope, Pa., where he excelled in basketball, football and track and was inducted into the sports hall of fame. He attended Bard in Annandale-on-Hudson, N.Y., and completed his bachelor’s degree in speech and dramatic art at the University of Iowa in 1972.

His first marriage, to Joanne Whitty, ended in divorce. He was separated from his wife of 33 years, the former Patricia Noonan. Survivors include two children from his second marriage, Zachary Brooks of Frederick and Jori Blouin of Philadelphia; a sister; and a stepsister.

After leaving WHFS, Mr. Brooks managed and promoted bands and ran a real estate title company before going into ad sales for radio stations in Frederick. He spent 13 years with WAFY-FM before retiring in 2019 from WFMD/WFRE, owned by communications behemoths including Clear Channel and iHeartMedia.

He told the News-Post that he was surprised to find himself working for corporate radio: “ ‘The Big Monster’ — something I detested.” But he offered that it was one of many changes with which he had come to peace.

“Little Feat was up in Frederick to play the Weinberg (Center for the Arts) recently and I hadn’t seen them in 30-plus years,” he said. “I remembered the last time I talked to them it was all ‘sex, drugs and rock ‘n’ roll,’ but this time it was all about physical ailments, the cost of tuition for our kids — old guy talk.”