Shinwell was born in Spitalfields, London, but his family moved to Glasgow, Scotland.
His father was a Polish Jew who had a small clothing shop, and his mother, a Dutch Jewess, was a cook from London.
He was the eldest of thirteen children.

He educated himself in a public library and at the Kelvingrove Art Gallery.
He enjoyed sport, particularly boxing, and he was the trainer of a local football team.
He left school at age eleven to be apprenticed as a tailor, and began his working life as a machinist in a clothing workshop.
In 1903, he became active in the Amalgamated Union of Clothiers' Operatives, and joined the Glasgow Trades Council in 1906 as a delegate of that union.

In May 1911, he was seconded to help organise the seamen of Glasgow at the request of Havelock Wilson of the National Sailors' and Firemen's Union (NSFU).
He played a prominent role in the six-week Glasgow seamen's strike which began on 14 June and which was part of a nationwide strike.
He subsequently became the secretary of the Glasgow branch of the NSFU.
In August 1912, he participated in a revolt against the union, which resulted in the Glasgow branch becoming part of the Southampton-based British Seafarers' Union (BSU).
He was the local secretary of the BSU until it became part of the Amalgamated Marine Workers' Union (AMWU) in 1922, after which he served as National Organiser of the new organisation.

In 1918, he stood unsuccessfully for Linlithgowshire (alternative name West Lothian).

In 1919, he gained national notoriety through his involvement in the Glasgow 40 Hours' Movement.
This movement culminated in clashes between police and protesters in Glasgow's George Square in January 1919, in which he was alleged to have been involved.
He was afterwards tried for incitement to riot and was sentenced to five months' imprisonment in Calton Jail, Edinburgh.
Shinwell was born in Spitalfields, London, but his family moved to Glasgow, Scotland. His father was a Polish Jew who had a small clothing shop, and his mother, a Dutch Jewess, was a cook from London. He was the eldest of thirteen children.
He educated himself in a public library and at the Kelvingrove Art Gallery. He enjoyed sport, particularly boxing, and he was the trainer of a local football team. He left school at age eleven to be apprenticed as a tailor, and began his working life as a machinist in a clothing workshop. In 1903, he became active in the Amalgamated Union of Clothiers' Operatives, and joined the Glasgow Trades Council in 1906 as a delegate of that union.
In May 1911, he was seconded to help organise the seamen of Glasgow at the request of Havelock Wilson of the National Sailors' and Firemen's Union (NSFU). He played a prominent role in the six-week Glasgow seamen's strike which began on 14 June and which was part of a nationwide strike. He subsequently became the secretary of the Glasgow branch of the NSFU. In August 1912, he participated in a revolt against the union, which resulted in the Glasgow branch becoming part of the Southampton-based British Seafarers' Union (BSU). He was the local secretary of the BSU until it became part of the Amalgamated Marine Workers' Union (AMWU) in 1922, after which he served as National Organiser of the new organisation.
In 1918, he stood unsuccessfully for Linlithgowshire (alternative name West Lothian).
In 1919, he gained national notoriety through his involvement in the Glasgow 40 Hours' Movement. This movement culminated in clashes between police and protesters in Glasgow's George Square in January 1919, in which he was alleged to have been involved. He was afterwards tried for incitement to riot and was sentenced to five months' imprisonment in Calton Jail, Edinburgh.
Manny Shinwell