As a 10-year-old boy, Walt Hays chased butterflies with the children of Theodore Hoover — brother of President Herbert Hoover — at Rancho del Oso, the Hoovers' private family retreat.

The land, near the Pacific coast and the Santa Cruz Mountains, is now part of Big Basin State Park. "It makes you love nature. It's a beautiful, beautiful area," home to fond childhood memories, Hays said.

As Hays grew and matured, so too did his concern for nature, leading him to advocate for stewardship and sustainable living — before such ideas were in vogue.

During the 1980s and early 1990s, even forward-thinking Palo Alto leaders dismissed the notion of sustainability, he said.

"They misunderstood it as sustaining our materialistic way of life," he said. Memorably, June Fleming, then city manager, went so far as to forbid city staff to use the word "sustainability," he said.

Instead of retreating from the issue, Hays taught rising leaders about sustainability as he saw it, defined by the "Three Es" of environment, economy and equity.

Suddenly, there were champions for sustainability everywhere, such as past mayor Jim Burch, City Manager Frank Benest and Assistant City Manager Emily Harrison, he said.

"Now, everybody on the council is in favor of it," he said, his eyes twinkling.

His commitment to environmental protection has spanned decades. For example, from 1976 to 1980, Hays was volunteer counsel for the California Solar Energy Industry Association. Twenty years later, he planned a sustainable-building tour, collaborating with the energy association and groups such as Hidden Villa, in celebration of Earth Day.

Civic responsibilities — and challenges — have excited and motivated Hays since the start of his professional life. After earning his law degree from Stanford Law School and working briefly in San Francisco in the early 1960s, Hays moved to San Jose in hopes of landing positions with more responsibility and leadership potential.

He practiced as a civil trial lawyer for 32 years before retiring in 1994.

While building his career, he led civic projects, headed the Sierra Club's Loma Prieta chapter and served as a San Jose City Councilmember from 1969 to 1973.

He moved to Palo Alto in 1976.

Getting to know residents in nearby East Palo Alto influenced his social views, his identification with issues and ultimately his political party. He said he saw how "people's needs were not being met and government should do more to help."

Outside working hours, Hays did much to help others — particularly through his active engagement in community organizations.

For three decades, he collaborated with fellow Palo Altans in Creative Initiative Foundation, Beyond War and the Foundation for Global Community. Through these groups, he promoted peace and worked to assist neighbors near and far.

No task was too small — or too dirty — for Hays when he served the Peninsula Conservation Center Foundation, now Acterra, as a board member, board president, project leader, grant writer, pro bono legal consultant, creek-cleaner, barn-deconstructer and habitat-restorer.

He constructed play space at the Palo Alto Junior Museum and maintained trails at Big Basin Park as Palo Alto's Rotary Club president.

As chair of the club's World Community Service Committee, he took his service work abroad: to Guatemala to improve water access; to Honduras to work on village banking and reforestation; to the Holy Land to promote peace; and to Kenya to help introduce biointensive agriculture.

In the mid-'90s, he directed World Community Service work for 58 Rotary Clubs, from Oakland to Watsonville. This earned him a Rotary Club award for outstanding leadership in June 1998.

Rather than rest on his laurels, he traveled just months later to Ghana to support polio eradication efforts.

Other closer-to-home contributions include working on sustainable building at Hidden Villa, judging a pollution-prevention award program, planting trees and constructing housing for Habitat for Humanity with Gunn High School students.

In the 2000s, he developed a plan, as co-chair of the Zero Waste Task Force, to reduce Palo Alto's waste by 2015. As the chair of the Mayor's Green Ribbon Task Force, he recommended ways the city should address global warming.

He organized a rally through Step-It-Up Silicon Valley to fight global warming. He also gathered faith-group representatives during the Mid-Peninsula Interfaith Convocation on Climate Action.

Coordinating neighborhoods, faith groups, businesses and Stanford University for environmental work continues to be his focus at the Community Environmental Action Partnership.

He installed photovoltaic cells on Escondido School — and for seven years has served as a docent for Environmental Volunteers, teaching kindergarteners and grade-schoolers about the world and their place in it.

By organizing "Green Teams" in Palo Alto schools, he is engaging the next generation of leaders. For the future, Hays envisions a greener Palo Alto.

"I feel the best about sustainability ... on the local level. You can see things happening," he said.

When he imagines the world his grandchildren will inherit, some circumstances worry him greatly: wars, refugees and other global crises could take a century to reverse, he said.

But if a spirit of volunteerism thrives in the next generation, then there is reason for hope, he said.

"If civilization is to continue, we need people to volunteer," he said. "The best thing to avoid being discouraged about something is to do something about it."