What political roles has Zack Polanski held and when did he join the Green Party?

1. From theatre to party: the early political step

Polanski’s route into party politics began after a career in community theatre and other work; according to his own background notes he joined the Green Party in 2017, which marks the formal start of his party membership and political ascent ^[1]. That membership preceded his rapid elevation within the Greens and set the stage for subsequent elected roles inside London and national party structures ^[1].

2. London Assembly: elected representative and committee chair

Polanski is a member of the London Assembly, a position he has used to focus on environmental and cost-of-living issues; the record shows he was re-elected to the Assembly in May 2024 and was re-elected as Chair of the London Assembly Environment Committee in June 2024 ^[2]. Coverage repeatedly cites his role on the Assembly as part of his political platform and a base for his public profile ^{[3] [2]}.

3. Deputy Leader: a springboard to national leadership

The Green Party elevated Polanski to Deputy Leader in 2022, a role he held through to 2025 and which the party and press identify as a key factor in his national visibility and electoral credibility leading into the leadership contest ^{[2] [4]}. Observers credit his time as deputy with sharpening the party’s media profile and helping drive the Greens’ electoral gains that followed the 2024 general election ^{[4] [5]}.

4. Leader of the Green Party: mandate, style and timing

Polanski was elected Leader of the Green Party of England and Wales in early September 2025; party announcements and major outlets record his victory and the start of his leadership on or around 2 September 2025 ^{[3] [4] [6]}. Reporting highlights that his campaign and subsequent messaging emphasize “eco-populism,” a move away from technocratic presentation toward a more emotive, mass‑membership approach ^{[4] [7]}.

5. Political positioning and priorities under Polanski

As leader, Polanski has foregrounded an agenda linking economic hardship to environmental policy, advocating measures such as a wealth tax and framing higher wages as central to a “green economy” ^{[2] [8]}. The media notes his stated aim to build a “green left” capable of challenging Labour and to broaden the party’s appeal beyond its traditional base ^{[6] [4]}.

6. How the press frames his rise: praise, caution and controversy

Mainstream coverage tracks a swift surge in Greens’ membership and polling after his takeover, and outlets credit his communication style for that momentum ^{[9] [10]}. At the same time, critics and political opponents have pushed back—Labour has questioned past positions such as comments on NATO—and some commentators urge scrutiny of his media tactics and policy claims ^{[6] [11]}. The press therefore presents both enthusiasm for short-term gains and caution about long-term strategy and consistency ^{[9] [11]}.

7. What’s not in these sources

Available sources do not mention any ministerial office held by Polanski, nor do they report him ever serving as an MP; they instead describe his elected role on the London Assembly and party leadership posts ^{[2] [4]}. Details about the internal vote tallies and exact dates of his deputy-leader appointment in 2022 beyond the year, or granular timelines of internal party roles before 2022, are not exhaustively documented in the supplied material ^{[2] [4]}.

8. Bottom line for observers and voters

Polanski’s political résumé in current reporting is straightforward: Green Party member since 2017, London Assembly member (re-elected 2024), Deputy Leader from 2022 to 2025, and elected national Leader in September 2025 ^{[1] [2] [3]}. He leads a party that has recorded recent electoral gains and rising membership, and his leadership style—branded “eco-populism”—is driving both renewed attention and contested assessments of the Greens’ future direction ^{[5] [4]}.