The 40-year-old mother of two died at a Canberra hospice on September 8, a day after receiving a Medal of the Order of Australia for her work on behalf of other cancer sufferers.
The Love for Connie service started at Melbourne's St Paul's Cathedral at 4.15pm on Saturday.
“Almost a third of her life, Connie had cancer. But she still had the ability to lift so many of us up," Connie’s husband Michael Johnson said.
“And in actively dying, she taught us so much about actively living.”
Mr Johson said he was impressed with what Connie achieved as an activist, saying that her message inspired thousands of people.
"It's a simple message: 'now is awesome, be aware of now'," Mr Johnson said.
"She often said to live life and not be afraid.
“We are all poorer for her death but we are infinitely richer for her dying."
"Thank you for taking our Con into your hearts, for wrapping your arms around this amazing woman. You all did an amazing job. Well done. Keep going."
A live update video was posted to the Love Your sister Facebook page