He made his first-class debut for Central Districts against Wellington as a batsman in a Plunket Shield match at Basin Reserve in December 1968 aged 22.

Two months later he made his maiden first-class century for South Island at Dunedin against the touring West Indian side, also keeping wicket for the first time at that level.

Owing to his superior batting potential he was selected ahead of incumbent keeper Barry Milburn, who had been first choice during the earlier home Test series against the West Indies.

His highest Test innings was 80 against Australia at Melbourne in 1974 and in the same season he made a century against them in a One Day International at Christchurch.

Wadsworth held the record with Bevan Congdon for the highest sixth-wicket partnership in ODIs for New Zealand against all countries with 130 runs at Christchurch in 1973–74 against Australia.