Charged with a 25-strong media team, Ward arrives after two years as deputy head of news at the Home Office, where she reported to head of press John Toker.
She spent six years at the Home Office and was previously at the Department for Transport, where she started her career in 1989.
Ward reports to director of communications Yasmin Diamond at what is the third-biggest Whitehall communications department after the Ministry of Defence and the Department for Trade and Industry (PRWeek, 4 February).
She takes over from Martyn Smith, who has retired, according to the department.
Fresh comms challenges for Defra include calls to cull badgers as part of a move to tackle the spread of tuberculosis in cattle.
A group of 300 vets called for a cull last week and Defra will consider the option if new scientific tests prove it would be effective.
The issue is destined to evoke strong feelings both from animal rights groups and the farming industry, which has long blamed the nocturnal animals for the spread of the disease.
Defra also plays a role in raising awareness of environmental issues, such as declining fish stocks. The department recently released a report on the damage that fishing and climate change has done to UK marine life.
Defra engages with the European Union and is involved with global policy making, in a bid to give its work a strong international focus.
'Defra is very different from the Home Office, it is more proactive,' said Ward. 'We are dealing with issues such as climate change and we want to use our role internationally to influence policy.'
Defra was created in 2001 when the Ministry of Agriculture, Fisheries and Food merged with the environmental and countryside areas of the then Department of the Environment, Transport and the Regions.
Ward's post at the Home Office has been filled by Linda Martin, who was previously assistant communications director.