Richard Sherman, who has died aged 95, often said that he never realised his youthful ambition to write “the great American symphony”. However, with his brother, Robert Sherman, he co-wrote songs that provided the soundtrack for a generation’s childhood – upbeat numbers with a homespun philosophy typified by lines such as “a spoonful of sugar helps the medicine go down”.

Those words were written for the brothers’ greatest triumph, the Oscar-winning Mary Poppins (1964), for which they created a score of staggering brilliance: haunting ballads, lilting lullabies, roistering marches, energetic dance numbers and knockabout vaudeville tunes. Half of the songs instantly became standards – not just the Oscar-winning Chim Chim Cher-ee but also A Spoonful of Sugar, Feed the Birds, Jolly Holiday and Supercalifragilisticexpialidocious.

They went on to write similarly memorable songs for The Jungle Book (1967), Chitty Chitty Bang Bang (1968) and Bedknobs and Broomsticks (1971).

The brothers first came to the attention of Walt Disney himself when they demoed a song for his TV series Walt Disney’s Wonderful World of Colour. Disney gave approval with his standard, understated accolade (“That’ll work”) and invited them to submit songs for The Parent Trap (1961). The result was Let’s Get Together, sung as a duet by Hayley Mills (playing twin sisters), which reached the US Top 10.

Disney next tasked the Shermans with suggesting song ideas for his planned adaption of PL Travers’s Mary Poppins books. Selecting various chapters, they proposed a cohesive storyline for the episodic adventures, relocated the 1930s narrative to Edwardian London of 1910 and composed numerous song sketches. Their choice of story elements coincided with Disney’s own and, following his keen instinct for talent, he signed the brothers – or, as he dubbed them, “the Boys” – as resident studio songwriters.

Despite the problems of dealing with Travers, an author with set ideas about her heroine – events chronicled in the film Saving Mr Banks (2013) – Mary Poppins proved a triumph for Disney, his star, Julie Andrews, and the Shermans, who won Oscars for best score and best song.

Richard credited this success to his father’s songwriting advice: “Make them singable, simple and sincere.” Whatever the style and tempo, Sherman songs had hummable melodies carrying memorable refrains, clever rhymes and inventive wordplay.

Richard was born in New York, the younger son of Russian-Jewish immigrants, Al Sherman and Rosa Dancis. Showbiz was in the blood: Rosa acted in silent films and Al was a Tin Pan Alley songwriter, responsible for a string of hits for major recording stars from Eddie Cantor to Billie Holiday. Work eventually took the Sherman family to California, where Richard attended Beverly Hills high school.

In 1946 he went to Bard College, in New York state, to major in music, studying the flute, piccolo and piano. His love of the great American show composers, along with British songwriters such as Ivor Novello and Noël Coward, encouraged an ambition to write for the musical stage.

In 1951, while Richard was sharing a flat with Robert, then an aspiring novelist and poet, their father challenged them to collaborate as songwriters. Richard recalled: “He said, ‘I bet you guys couldn’t pool your talents and come up with a song that some kid would give up his lunch money to buy.’” Their first collaboration to be recorded was that year’s Gold Can Buy Anything (But Love) sung by Gene Autry.

Richard joined the US army reserve in 1953, serving his time in California as a military bandleader until his discharge two years later.

His brother was collaborating with the songwriter Bob Roberts when, in 1959, Richard joined them to write Tall Paul, a rock-and-roll number that was a hit for Annette Funicello, the popular Mouseketeer on Disney’s TV show The Mickey Mouse Club. Another Sherman brothers’ number, You’re Sixteen (1960), was a Top 10 hit in the UK and the US for Johnny Burnette. Ringo Starr’s cover version reached the Top 10 in the UK in 1974.

Following the success of Mary Poppins, when Disney produced four attractions for the 1964 New York World’s Fair, Sherman words and music were an essential component of their success, most notably their up-beat anthem to positivity, There’s a Great Big Beautiful Tomorrow, and, for a Pepsi-sponsored tribute to Unicef, It’s a Small World. Later installed in Disneyland and the company’s five other international parks, the song (performed by dolls of children in national costumes) is permanently playing somewhere in the world 24/7 and is one of the most insidious earworms in the history of popular music.

The Shermans’ songs for other Disney park attractions include several written in 1982 for Walt Disney World’s Epcot Center in Florida.

For a time, the Sherman brothers used headed notepaper with faux engravings of Robert as WS Gilbert and Richard as Arthur Sullivan indicating their respective contributions, but their work was not so neatly defined. Collaboration began not at the piano, but with discussion (and argument) as they sought a “hook” in the characters or storyline on which to hang a song. They approached each project together but from different angles; as a result, said Richard, their songs were “never too sugary and never too salty”.

For a decade they wrote for Disney film, TV and animation projects, among them In Search of the Castaways (1962), Summer Magic and The Sword in the Stone (both 1963) and Winnie the Pooh and the Honey Tree (1966), the first of three short films based on the stories of AA Milne.

The Happiest Millionaire (1967) featured an inventive score and a starry cast (Fred MacMurray, Tommy Steele, Greer Garson) but failed to match the success of Mary Poppins. The Jungle Book, released the year after Walt Disney’s death, provided Louis Prima and Phil Harris with the zany scat-duet for orangutan and bear I Wanna Be Like You, and the hypnotic Trust in Me. The Aristocats (1970) featured a Parisian title song that was Maurice Chevalier’s final recording.

The Shermans’ career at Disney ended with Bedknobs and Broomsticks, which earned them two more Oscar nominations, including best song for Angela Lansbury’s The Age of Not Believing. The score also featured The Beautiful Briny, an underwater song-and-dance number for Lansbury and David Tomlinson, originally written for an unused sequence in Mary Poppins.

When the James Bond producer Albert R (Cubby) Broccoli asked Disney to co-produce a film based on Ian Fleming’s children’s book Chitty Chitty Bang Bang, Disney declined but offered to release the Shermans from their contract so they could work on the film. The resulting hit British musical, starring Dick Van Dyke, featured the Oscar-nominated title song along with such numbers as Truly Scrumptious and Hushabye Mountain. Despite being a non-Disney project, it proved the closest thing to a Poppins sequel.

In 2002, with several new songs by the Shermans, Chitty Chitty Bang Bang began a record three-and-a-half-year run at the London Palladium. This success was followed in 2004 by a stage version of Mary Poppins. Both shows went to Broadway and enjoyed national and international tours. In 2013, Richard consulted on a theatrical interpretation of The Jungle Book.

Their other American stage shows include Victory Canteen (1971), Over Here! (1974), featuring Maxene and Patty Andrews (of the Andrews Sisters) and newcomer John Travolta, and Busker Alley (1995) starring Tommy Tune. Later films include Snoopy, Come Home! (1972), the Hanna-Barbera animated version of EB White’s Charlotte’s Web (1973) and three projects for which the Shermans also wrote the screenplays: Tom Sawyer (1973), Huckleberry Finn (1974) and The Magic of Lassie (1978).

They also collaborated with Bryan Forbes on The Slipper and the Rose (1976) for which their evocative title waltz received an Oscar nomination. In 2000, the Shermans returned to Disney for The Tigger Movie. They received many awards including, in 2008, the National Medal of Arts.

Following Robert’s death in 2012, Richard contributed a number to the musical revue LA Now and Then, in 2016; the song, celebrating the early days of the Disney studio, was aptly titled The Whimsy Works. He also wrote songs for the 2018 film Christopher Robin. Richard himself appears in the end credits, singing and playing Busy Doing Nothing on the piano.

In Once Upon a Studio (2023), he was filmed playing Walt Disney’s favourite Sherman song, Feed the Birds, on the same piano on which he had originally played it for the boss almost 60 years before.

Richard collaborated with other songwriters but he never rivalled the work created with his brother. In contrast to the happy-go-lucky songs, their personal rapport was often far from harmonious, as painfully revealed in the 2009 documentary The Boys: The Sherman Brothers’ Story.

Without friction, Richard maintained, there would have been no sparks of inspiration: “I was an extrovert and Bob was an introvert but we closed the door and it was just us and the music.”

A lyric in the score for Charlotte’s Web runs: “I used to think the sum of one and one was two / But we add up to more, me and you.” And Richard will, for ever, be associated with his brother for a songbook filled with funny, touching, romantic, optimistic, singalong numbers.

Richard was married twice. His first marriage, to Corinne Newman in 1948, ended in divorce. In 1958, he married Elizabeth Gluck. She survives him, as do their two children, Gregory and Victoria, and his daughter, Lynda, from his first marriage.

• Richard Morton Sherman, composer and songwriter, born 12 June 1928; died 25 May 2024