My friend Monty Passes, who has died aged 98, was a successful businessman, art collector and academic. Through the business investments he made in the 1950s and 60s, in women’s clothing and hairstyling, and promoting jeans as a fashion item, he played a part in shaping the “look” of mid-20th-century Britain.

Monty was born in Highgate, north London, to Rebecca (nee Schwalbe) and Albert Passes, both from immigrant Jewish families. He and his brother, Norman, attended University College school, Hampstead. Monty left at 14, joining his father’s handbag manufacturing business. He enlisted for military service in June 1940 and his first night in the army was spent in Hammersmith library. During artillery training later that year, at Wormwood Scrubs, he received an ear injury that meant he was invalided out.

After the second world war, in partnership with Charles and Monty Burkeman, Monty established a women’s garment manufacturing company with the label Charmont. This company became a nationwide operation and was ultimately listed on the stock exchange as Helene of London. The two Montys also backed the young hair stylist Vidal Sassoon, investing in his first two salons. A fellow businessman, Willi Gertler, advised them to import blue jeans – then viewed as workers’ clothing – and they became the first and exclusive European traders for Levi’s, with enormous success.

Monty’s keen eye extended to art, and he and his second wife, the American actor Barbara Cooper, amassed a largely European and British post-impressionist collection.

He retired in the 70s and returned to education. After a BA in English literature at what is now Middlesex University, he took a master’s in political philosophy at the London School of Economics in 1985, then started PhD studies at the LSE in 1991.

According to Professor Rodney Barker, Monty’s PhD supervisor, he was constantly inspired by the experimental and the unexpected – in art, literature and politics. If you mentioned a review of a new book, Monty would already have read it. He achieved his PhD aged 73 with a thesis on the Christian socialist RH Tawney.

Monty was a founder member of the leftwing discussion group the Anjou Club, which met monthly at the Gay Hussar restaurant in Soho. In the 50s, he supported and befriended various blacklisted American actors and directors, such as Sam Wanamaker, who found refuge in Britain from Joseph McCarthy’s communist witch-hunts. Monty was a lifelong member of the Labour party.

His long, active and socially engaged life was marred by dementia in his final years.

Barbara, whom he married in 1955, died in 2011. Monty is survived by their daughter, Patricia, and by three children, Alan, Judith, Barbara, from his first marriage, to Betty Glicksmann, which ended in divorce; and by seven grandchildren and eight great-grandchildren.