ALEX McEwen, who has died aged 73, was a pioneer who paved the way for America's love affair with Scottish folk music. Back in the mid-1950s, 20 years before groups such as Battlefield Band, Silly Wizard and Ossian made commuting across the Atlantic part of the professional Scottish folk musician's life, and before even Jean Redpath exported her talents, McEwen and his older brother, Rory, were wooing audiences in New York, Los Angeles and San Francisco and playing their Scots ballads to as many as 40 million television viewers.

They even recorded for the Smithsonian's Folkways label and on one particularly notable occasion, McEwen was able to call on Bob Dylan as his accompanist in a Greenwich Village folk club.

McEwen, who later became a familiar figure with Rory on the BBC's Tonight programme and through his own Scottish Television series, Alex Awhile, was born in Marchmont House in Berwickshire, one of Conservative politician Sir John McEwen and Lady Bridget McEwen's seven children. He was educated at Eton, where Rory was three years above him, and the brothers developed a passion for jazz and country blues as well as learning Scottish ballads and folk songs, accompanying themselves on guitars.

After McEwen completed his national service with the Cameron Highlanders, the brothers set off on an American adventure in 1955, looking to see and hear as many as possible of their musical heroes who were still performing. Arriving in New York, they stayed with Alice Astor, whose daughter Romana would later marry Rory, and hit the clubs and bars. Many of their heroes, including Pete Seeger, were caught up in the McCarthy-era performance ban for their perceived un-American activities, but being from Scotland, McEwen and Rory were able to play anywhere - and they did, entertaining at weddings and parties and playing venues where they passed a hat around the audience.

After a few weeks in New York, they set off for the south with friends, taking in New Orleans and driving over to El Paso, Santa Fe and Cripple Creek, where they secured their first official professional gig, playing twice a day in a bar. From there they headed for San Francisco and Los Angeles and back to New York, by which time they were reaching the attention of record producers and television executives. They recorded two LPs, Great Scottish Ballads and Scottish Songs and Ballads, for the prestigious Folkways label and were invited to appear for two consecutive nights on the Ed Sullivan Show (on which The Beatles later made their American breakthrough) and the Arthur Godfrey Show, where they reached an audience of 40 million and returned for a further two appearances.

Such was their impact that they had to get used to being recognised in the streets and mobbed for autographs. After Rory returned to the UK, McEwen stayed on in New York, learning Delta blues guitar first-hand from the Rev Gary Davis in Harlem. He then followed Rory and joined him on the BBC's nightly news and current affairs programme Tonight, where Rory was performing topical calypsos, specially written on the day with Bernard Levin. The brothers then became popular guests on London's folk and blues club scene, including the Ballads and Blues Club, where they appeared alongside Alexis Korner and Long John Baldry.

In 1960, McEwen married Princess Cecilia of Weikersham, an Austrian with family ties to Queen Victoria, and the McEwens' social group expanded to include model Jean Shrimpton, actors Terence Stamp, James and Edward Fox, and Beatle George Harrison as well as Bob Dylan and old friends including Princess Margaret.

Professionally, things remained on the up, too, with appearances at the Edinburgh Festival leading to recordings with Joan Baez's future brother-in-law, Richard Farina and his then wife, the iconic Texan folk singer Carolyn Hester (on the EP Four for Fun), and alongside jazz musicians George Melly, Sandy Brown and Al Fairweather on Plain Song & All That Jazz.

When Rory decided to concentrate on painting in 1962, McEwen continued as a singer and guitarist, hosting Alex Awhile for STV, on which he featured blues, American and British folk music and calypso, until he, too, retired from the music business.

He joined John Menzies in 1965 and rose to personnel director, became an art dealer and farmer and devoted much time to fishing. Publicly, however, his contribution to music is perhaps his greatest legacy, being cited as an influence and inspiration by Billy Connolly, Van Morrison and many others. He is survived by his wife, Cecilia, his daughter, Sophie, sons Alexander and Hugo and five grandchildren.