The Labour leadership hopeful said the race to replace Jeremy Corbyn had been “pretty gruelling” as she set about garnering support through a number of interviews.
On ITV’s Good Morning Britain, the shadow foreign secretary spoke about her family being made homeless when she was a young child.
She said: “We have to be the party of opportunity.
"We have to be there to give everyone a leg up so everyone gets an equal chance.”
Frontrunner Sir Keir Starmer last night became the first candidate to get onto the leadership ballot after landing the endorsement of the Usdaw union.
Left-winger Rebecca Long-Bailey is expected to follow suit when Unite meets on Friday.
Neither Ms Thornberry nor contender Jess Phillips are tipped to be endorsed by any of the big five trade unions which means they will need considerable support from local party branches to avoid elimination.
Supporters of Lisa Nandy were hoping she would get the endorsement of the GMB union today.