Ronald Herbert “Whodaguy” Jacobs, a Hawaii-born broadcaster who helped introduce rock ’n’roll to the islands and went on to become a pioneer in the U.S. radio industry, died Tuesday.

Jacobs, who had been in declining health, died at his Pearl City home Tuesday morning. He was 78.

“Words cannot express my sorrow at the loss of my great friend and former colleague,” said Tom Moffatt, former broadcaster and longtime Hawaii concert promoter.

Born in Honolulu to Raymond and Shirley Jacobs on Sept. 3, 1937, Jacobs attended Punahou School through the ninth grade, transferred to Roosevelt High School and later dropped out to pursue a career in radio. He earned his Federal Communications Commission radiotelephone operator’s license at age 17 and started his career at the old KHON radio, working the overnight shift.

“A true radio pioneer with a genius few could fathom, Jacobs broke new ground in the industry here in Hawaii, first with Henry J. Kaiser’s KHVH station, then KPOA, then KPOI with the ‘Poi Boys’ and on the mainland as the brain behind the revolutionary and award-winning “Boss Radio” format at KHJ in Los Angeles,” Moffatt said in a statement.

The “Boss Radio” format Jacobs co-created with former competitor Bill Drake in the 1960s took KHJ in Los Angeles to No. 1 in the second-largest market in the U.S. and revolutionized American radio. At KHJ, he also produced a so-called “rockumentary” titled “The History of Rock and Roll.”

Prior to leaving for the mainland, Jacobs, Moffatt, Tom Rounds and Mel Lawrence created Arena Associates and promoted the first concerts at the H.I.C. Arena, now known as the Neal Blaisdell Center.

Numerous sets of call letters in Hawaii and major markets, mostly in California, fill Jacobs’ resume. Also, he was a founder of the company that produced the long-popular radio show “American Top 40,” hosted by the late Casey Kasem.

To Maui broadcaster Ed Kanoi, Jacobs was a mentor from the day they met. “I was such a fan,” Kanoi said. “He taught me so much about doing radio. With him every detail was so important.”

Years after working together at KKUA-AM 690, Jacobs helped Kanoi land a job in Los Angeles. They last saw each other in January when Kanoi drove Jacobs to the celebration of life for another radio personality, the late Phil Abbot. “He was in really good spirits,” Kanoi said of their visit.

In the 1980s, Jacobs and radio host Mike Buck worked together at KGU, then in the Waikiki Business Plaza. “He did morning drive, I did afternoon drive, and the TV commercial for us was: ‘From Aku and Luck to Jacobs and Buck, all you need to know on the radio,’” Buck said. “It was when we launched the first all-talk format,” and Jacobs “insisted on playing snippets of music so he could call it ‘Talk &Roll.’”

Jacobs helped launch the careers of scores of Hawaii singers, songwriters and musicians via the “Home Grown” album series started in the 1970s, produced initially during his years at KKUA, then a top-40 radio station. Among the artists whose careers took off include Nohelani Cypriano, Danny Couch and John Keawe.

Jacobs was presented a Na Hoku Hanohano Lifetime Achievement Award in May by the Hawaii Academy of Recording Arts, to which his friend and caregiver Brian von Ahsen accompanied him.

“He hadn’t been in front of an audience for a long time, and you know, he was a pro. He knocked it out of the park,” von Ahsen said of Jacobs’ speech. “He was very humorous, very topical, there were lots of jokes and he had lots of notes, but there were all kinds of people in the audience, and with his encyclopedic knowledge of music and the people involved, he could draw from that” spontaneously, he said.

In the 1990s, Jacobs was an early producer of an Internet radio show promoting Hawaiian music via the Web, and was honored by the state Legislature for his contributions in the area of Hawaiian music. He wrote a blog, active until 2014, and was seemingly ever-present on Facebook.

In addition, Jacobs wrote books including “Obamaland: Who is Barack Obama?” as well as “KHJ: Inside Boss Radio” and “Backdoor Waikiki.”

Carol Williams, whose husband, John, worked with Jacobs at KHJ, edited some of his books, she said.

“He challenged me constantly to be better at what I do, and he was very appreciative,” she said. “His memory was amazing. He could reel off facts and figures from years and years ago, and he researched everything … and expected everyone else to do the same,” she said.

Jacobs is survived by a daughter, Miki DeVivo, in Arizona.

Information on services is not yet available.