Kristen, mother of seven-month-old Morrison, said she hoped no mother ever had to go through what she went through.

"The last 24 hours have been really traumatic for us and our family. I really hope no one ever has to experience what we went through," she said through tears.

"An act of kindness that turned so sour. But he's home and he's well and been on an adventure without mummy."

Kristen was driving her Mazda Protege about 2pm on Thursday when she stopped to help a man whose car had broken down in Ngunnawal.

While stopped on the side of the road, the man jumped into her car and fled with her seven-month-old in the back.

The theft prompted a frantic two-hour search, with police shutting down all routes out of Canberra, with all available patrol cars, the police helicopter and NSW Police called into assist in the search for the car.

About 3.40pm, police received the call that Morrison had been found alive and well by police on a porch, about 400 metres away in Palmerston.

The mother thanked the ACT community for their support and their help in finding the baby, after more than 130,000 people shared vital information on social media in an attempt to find her son.

Kristen was in tears as she expressed her thanks to ACT Policing, social media users, journalists and the general public in locating her baby.

"The overwhelming support that we had, we'll be eternally grateful for them helping him to be found. Thank you all so much," she said

"We're so happy that he's home. He just doesn't know that anything happened."

A 27-year-old man has been taken into custody in relation to the theft and will face court on Friday afternoon.