Smart, quick-witted and thoughtful, Norman's major achievement in his near decade-long stint as the Greens' male co-leader was to drag the party out of its Opposition mindset and prod it towards the mainstream and ultimately the levers of power. Not an easy task in a party where principles are not a disposable commodity.
In that regard, he turned the party's biggest weakness - its economic policy - into one of its strengths by arguing "Green economics" is "smart economics". It almost became his catch-cry.
There is little question that he desperately craved the chance to put elements of that policy into practice through securing a seat at the Cabinet table.
It was his very bad luck that his time as co-leader corresponded with Labour slipping from power and failing to win nearly enough seats in successive elections to put together a coalition government with the Greens.
His legacy is thus his crucial re-branding of his party's image away from the stereotypical view of its members as a bunch of lentil-munching Morris dancers. By donning a suit for the television cameras, he changed perceptions of the party overnight.
Norman may be going. But descriptions of the Greens as whacko and loony have long gone thanks to him.