Born in Bebington, Merseyside,[2] Nowak first joined a trade union at age 17 when he had a part-time job at Asda.

He became Vice President of the Wirral Trades Union Council at the age of 19 – the youngest person to hold the post.

[3] He is credited with ensuring that the Department for Business, Energy and Industrial Strategy (BEIS) guidance for safe working during the pandemic was significantly stronger than that first proposed by ministers.

He supported the then TUC General Secretary Frances O'Grady in securing the Job Retention Scheme.

In July 2022 the TUC announced that Nowak would be its next General Secretary, taking office from January 2023.