The last time I saw June Callwood, she was laughing.She’d been diagnosed with cancer and given months to live. I called her up and asked her to lunch, a final meal with my mentor. She dispensed wisdom between laboured breaths. I sat in awe of her optimism and energy.All her life she had championed unfashionable causes and overturned stigmas, creating a hospice for people dying of AIDS, establishing a shelter for women and children escaping abuse, and fiercely defending Canada’s invisible citizens, the homeless and poor.It hadn’t been an easy fight, but she was unbowed, laughing easily and often. She continued to think of others first. When we parted ways, she sped off in a zippy red convertible.I’ve thought of that meeting many times since her death in 2007. My office window at the WE Global Learning Centre in Toronto looks directly out at Jessie’s Centre, the haven Callwood founded for young pregnant women and mothers. Looking up from my desk, I have a daily reminder of Callwood’s work that serves as a welcome challenge to live up to her example.What was the secret behind Callwood’s happiness? She trusted others would carry on her fight.Callwood founded and helped steer 50 organizations in her lifetime, including the Canadian Civil Liberties Association and PEN Canada. She fought to formalize revolutionary services for people on the margins, from sex workers to AIDS victims.Although Callwood lived in Toronto, there are tireless activists like her in every city and town. But what keeps me thinking of her isn’t that she fought the good fight — it’s that she found a way to keep it going long after she couldn’t fight anymore.She made social progress sustainable before it became a buzzword. The organizations she founded are still around because of the groundwork she laid.She famously said the only way to make a difference is to gather a group. On that final afternoon we shared, she offered one more piece of wisdom. A lifetime is limited in what it can accomplish, she told me (though I’d consider this a direct contravention to her own example). But she was confident there were others coming up behind her to take the baton, to make the world a little more compassionate, a little more just.Too few people are aware of her impact. There’s a park and a street in Toronto that bear her name, and an annual award for service is given in her honour. Callwood herself wasn’t concerned with memorials. When I asked her about being remembered, she brushed the question off. Still, Canada ought to channel her spirit more often, and especially this month, which would have marked her 95th birthday.Her real legacy is in the lives she touched — the thousands of young mothers who find a community at Jessie’s Centre or begin to rebuild their lives at Nellie’s Shelter every year.Today, people compete to be the loudest while issues trend for a day and then are gone. June Callwood represents the antithesis to this. She lived a life of service and acted from a place of compassion, leaving a community to carry on her fight.Craig Kielburger is co-founder of the WE Movement, which includes WE Charity, ME to WE Social Enterprise and WE Day.