The Plainmoor outfit sit 23rd after winning just five of their 25 games this season, with the former captain taking now tasked with preserving the club's league status
The Plainmoor outfit sit 23rd in League Two and will hope former captain Hargreaves can turn the club's season around and ensure their Football League status come May.
"Chris has started work already and we are thrilled to have a new manager in place for the challenges ahead over the second half of the season," said Torquay chairwoman Thea Bristow.
Torquay have won only twice in the last 10 league matches and face a Wimbledon side who picked up their first victory in eight against Wycombe Wanderers last weekend.
One point separates the league's bottom three with managerless Northampton Town aiming to move off the foot of the table when York City visit Sixfields.
Interim boss Andy King has picked up four points from nine since Aidy Boothroyd was sacked and he will look for his players to avenge their 1-0 opening-day defeat at Bootham Crescent, which saw Ryan Jarvis score the winner a minute from time.
Bristol Rovers have won only one of their last four matches and sit above the drop zone on goal difference, but can boost their survival chances with victory against mid-table Exeter City, while Rochdale will hope to build on their FA Cup success at Leeds United.
Goals from Scott Hogan and Ian Henderson put Keith Hill's men through to the fourth round of the competition and attentions now revert to the league, with victory against Hartlepool United enough to take them second.
Southend United also claimed a Championship scalp in the cup, beating Millwall 4-1, and they travel to Plymouth Argyle with designs on the top three, while pacesetters Scunthorpe United welcome Mansfield Town.
Second-placed Burton Albion host Cheltenham Town and Chesterfield take on in-form Bury, with David Flitcroft's side eying a third straight win.
Fleetwood Town moved into the play-off spots with their 3-1 win over Accrington Stanley last time out and will look to remain there after their visit to Dagenham and Redbridge, with Graham Alexander hoping for a Portsmouth result against sixth-place Oxford United.
Morecambe welcome Wycombe Wanderers to the Globe Arena and Cheltenham Town make the trip north to Burton Albion looking to rekindle their hopes of reaching the play-offs.
Newport County will look to bounce back from defeat to bottom side Northampton when they face Accrington Stanley, who enjoyed an extra week of rest after their clash with Portsmouth on Saturday was postponed.