In addition to converting piano sonatas to guitar, Mr. Morel looked beyond a purist approach to classical composition. His songs — including “Pampero,” “Sonatina,” “Romance Criollo” and “Guitar Concerto” — reflected his roots, with Latin melodies, harmonies and rhythms from tango to samba. But they were also influenced by the jazz and other forms of music he embraced in his adopted hometown of New York.
Mr. Morel’s 1978 appearance at Manhattan’s Town Hall performance space dazzled New York Times music critic Joseph Horowitz, who called him an “extraordinarily suave guitarist [who] stylishly applies a broad range of color and dynamics, and scampers up and down the fingerboard with dazzling assurance.”
Horowitz highlighted Mr. Morel’s arrangement of Leonard Bernstein’s score to “West Side Story,” and said his take on the huapango rhythm of “America” was “ingeniously embroidered, and Mr. Morel’s performance was scintillating.”
In between classical concerts, Mr. Morel paid his bills by performing nightly at the New York jazz nightclub the Village Gate. At various times, he shared stages with pianist Erroll Garner, trumpeter Dizzy Gillespie and even country guitarist Chet Atkins, who helped promote Mr. Morel’s recording career, played some of his arrangements and became a lifelong friend. In return, Mr. Morel wrote a choro he dedicated to Atkins.
His early recitals — starting with his 1960s debut at Manhattan’s Carnegie Hall, on a bill with the Kingston Trio — offered compelling hybrids of jazz and classical pieces. They featured compositions by George Gershwin and Dave Brubeck as often as Spanish guitarist Andrés Segovia and Argentine pianist Fernando Bustamante. Mr. Morel arranged and played his own guitar version of Bustamante’s piano piece “La Misionera,” which has become a favorite of many younger guitarists.
His work had been recorded by countless guitarists, among them eminences such as David Russell and Pepe Romero.
Mr. Morel latterly became as noteworthy as a music educator as he was a performer and recording artist. He was an adjunct professor of music and classical guitar at the City University of New York’s Lehman College. During his annual European concert tour, his itinerary was specifically designed to emphasize his role as a musical mentor.
One British classical guitarist he helped inspire was Alexandra Whittingham, now 23, who was named young guitarist of the year in 2015 at the Gregynog Young Musician Competition in Wales. She often plays one of Mr. Morel’s best-known compositions, “Danza Brasilera” (Brazilian Dance), which he wrote in the 1970s. The piece combines rhythmic chords with dazzling arpeggio patterns and snatches of catchy melody, giving the essence of Brazilian music with its echoes of sambas and choros.
“Jorge Morel brought so much to the world of guitar,” Whittingham said. “His contributions to our instrument’s repertoire are unique in their compositional style and character, and will continue to inspire many generations of guitarists to come.”
Mr. Morel was born Jorge Scibona in Buenos Aires on May 9, 1931, to a family of Sicilian heritage. His father, a musician and stage actor, taught him the fundamentals of guitar. At 14, he became a pupil of guitarist and composer Pablo Escobar at the University of Musical Studies in Buenos Aires. Two years later, he gave his first professional performance on the radio, alongside Escobar.
Amid a hectic early musical career, he spent a few years living and playing in Puerto Rico, and at one of his engagements, he found an admirer in Vladimir Bobri, president of the New York Society of the Classic Guitar. It was at Bobri’s invitation that Mr. Morel came to perform and then settle in the United States. (He took the stage name of Morel at the suggestion of a friend, who said it would be easier for American audiences to remember.)
At his peak, Mr. Morel gave about 70 concerts a year on both sides of the Atlantic. As a soloist, he premiered his “Suite del Sur,” a concerto for guitar and orchestra, with the Los Angeles Philharmonic conducted by Zubin Mehta. The suite included “Prelude in Memory of My Wife,” dedicated to his wife, Olga Alvarez, a Puerto Rican model and dancer.
They were married from 1962 until her death in 1973. In addition to their daughter, of Orlando, survivors include a son from a previous relationship, Jorge Scibona of Buenos Aires; a grandson; and two great-grandchildren.
One of Mr. Morel’s greatest supporters, publishers, producers and promoters was Maurice Summerfield, a classical guitarist, author and businessman from Newcastle, England, who founded Classical Guitar magazine in 1982 and produced three recordings and 15 volumes of guitar arrangements by the Argentine.
“In 1979, I had never heard of Jorge Morel. All that changed after hearing Jorge play in concert for around 30 minutes at the 1979 National Association of Music Merchants in Chicago,” Summerfield said. “The half-hour concert spot before Jorge’s solo guitar recital was played by a 16-piece excellent big band in the style of Count Basie.
“I remember commenting what ‘bad’ programming it was to put a solo guitarist on after such a great big band,” he continued. “Well, I was wrong. I was privileged to hear some of the most amazing guitar playing and wonderful guitar arrangements that I have ever heard.”