She also showed clips of herself dancing in various places as evidence of her remarkable recovery.
Campbell's dramatic journey from near death to a return to health after her life-saving transplant April 6 has captured attention around the world.
The young woman's campaign is credited with a significant increase in people willing to donate their organs.
To the applause of a studio audience in Burbank, Calif., DeGeneres praised the enthusiastic Campbell, who needed oxygen during her last Skype appearance on the show in February.
"You look fantastic," DeGeneres said.
"I cannot believe it's been only seven weeks since you received your double-lung transplant."
"I feel so good," Campbell responded. "It's unbelievable how amazing this has been."
Campbell went from perfect health to near death due to a lung-hardening disease that was suffocating her, leaving a complicated double-lung transplant as her only survival option.
The major part of the recovery took about a month, Campbell said from Toronto.
"Every day I felt stronger and stronger. I was slowly able to tie my shoes again and then make my bed," she said.
"I gained the ability to live life again. It's just been such a miracle in such a short period of time."
Campbell, who made her first post-operation public appearance at a televised news conference on Thursday, has become a poster child for organ donations, driven in part by the earlier "Ellen" appearance and by an endorsement from pop idol Justin Bieber.
She noted that 18 people die each day in the United States waiting for a suitable organ, and said she hoped the "Ellen" exposure would help bring that number down.
"You've been a vehicle and driven this awareness to that extra level and got that many more people to sign up," Campbell told DeGeneres.
"Others who've been against organ donation now support it."
Saying she could not wait to meet her in person, DeGeneres promised to fly Campbell and her mother out to California for a live appearance on the show as soon as she was well enough to travel.
DeGeneres said they would "dance together."
"Your energy is what attracted me in the first place," DeGeneres said. "I loved your attitude."