The family's mills ran deep: David Ballantyne rented Caerlee Mills at Innerleithen — the first woollen mill in the Scottish Borders — and his son Henry founded Henry Ballantyne & Sons in 1847. After the 1920 merger, knitting began in 1921 to use up surplus yarn, growing into cashmere knitwear and, through intarsia technique, a lasting association with argyle patterns. By 1963 the firm employed 400 people, famed for the quality of its luxury cashmere.
Facing financial difficulty in the early 21st century, the brand was acquired in 2004 by the Italian fund Charme Investments and has since been operated from Italy; the original Scottish mill, Caerlee, closed in 2013. In 2014 designer Fabio Gatto acquired Ballantyne, refocusing it on knitwear as its core.