Meet the Team

Staff

Christopher Hartsfield

Programs Director

Bio

Christopher Hartsfield became CS' Programs Director in January 2020, overseeing daily direct service for nearly 400 children and youth as well as single-day programming for thousands of children and community members. From 2015 - 2018, Christopher led CS' Outdoor Play programming for 7-24-year-olds, including teaching after school children and youth interns how to co-lead cycling adventures, fitness circuits and testing, JungleGym (CS' obstacle race and active-living fair), and over 35 single-day play events per year. In 2019, Christopher transitioned to Programs Manager, leading program service delivery for CS’ Outdoor Leadership Academy - Summer Youth Employment Program and expanded its OLA-Kids programming from after school to summer camp. Christopher earned a B.S in Health & Physical Education from Elizabeth City State University, and has a Wilderness First Aid Certification from SOLO, a Middle Manager Certificate from the American Camp Association, and Outdoor Leadership Training from the Appalachian Mountain Club's Youth Opportunities Program. In 2019, Christopher completed the Developing Leaders Program for Nonprofit Professionals at Columbia Business School and the Family Development Credential for Leaders with the NYC Department of Youth. Prior to joining CS, Christopher was a fitness coach and floor trainer at the YMCA Armory in Park Slope instructing 4-18-year-olds in various sports classes and the youth basketball league. He is a licensed security and fire brigade officer, and demonstrates a serious commitment to safety.

Mac Levine, MPH

Founding Executive Director

Bio

Executive Director Mac Levine, MPH, founded CS in 2008 with 16 East Harlem children, and has since grown the organization to serve over 19,000 children, youth, and families. She earned a Masters of Public Health from Columbia University's Mailman School of Public Health in the Built Environment Track, where she won the John and Kathleen Gorman Public Health Humanitarian Award. Mac also graduated cum laude from Northeastern University with a bachelor's degree in music industry and a minor in sociology. Mac is a Certified Nonprofit Accounting Professional and a graduate of the National Outdoor Leadership School. She holds a Camp Director Certificate of Added Qualification from the American Camp Association and Wilderness First Aid. She was recognized in CUNY's 2017 Class of 40 Under 40: The Rising Stars in New York City Food Policy. She has guest lectured at Columbia University, New York University, Icahn School of Medicine at Mount Sinai, The New School, and Northeastern University, and presented at the Just Food, American Community Gardening Association, and Hindsight Conferences. She is a co-author of "Closing Health Disparities Through A Multi-Level Approach," published in the International Journal of Child and Human Development as well as in the book Environmental Health Disparities: Costs & Benefits of Breaking the Cycle in 2016. She has been honored by the 25th Precinct with a Women of Excellence Award. Mac was the first solo female to stand-up paddle (SUP) the Hudson River Water Trail without assistance from Albany to Manhattan in June 2014, and the first person to SUP all five boroughs on the NYC Water Trail in 2015. She has completed the NYC Skate Marathon twice.

Jean Marcellus

Outdoor Play Coordinator

Bio

Jean Marcellus is a dedicated youth development professional with over 20 years of experience empowering young people to reach their full potential. A proud graduate of Rice High School in Harlem, Jean went on to earn an Associate Degree in Criminal Justice from SUNY Farmingdale and played collegiate basketball for two years before taking his talents overseas, where he played professionally in Belize for four years.

His deep-rooted passion for youth mentorship and sports has fueled two decades of coaching and training basketball players at all levels. He dedicated 15 years working as a Crisis Youth Specialist and Supervisor at Special Act schools and residential sites in New York. Most recently he served as Dean of Discipline at Innovation High School in East Harlem.

Outside of his work, Jean enjoys traveling, exploring new music, and discovering great restaurants. He lives by the belief that It takes a village to raise a child, but you need a Chief to lead, a philosophy that continues to guide his mission in both business and community engagement.

Luz Thomas

Garden Educator

Bio

Luz Thomas serves as the Garden Educator at Concrete Safaris, where she oversees outdoor garden programming and environmental education initiatives for youth. In this role, she fosters curiosity, leadership, and a connection to nature through hands-on experiences that promote wellness and sustainability.

She earned her B.A. in Sociology and Education & Social Transformation from the University of California, Los Angeles (UCLA), where she focused on holistic growth through community-centered learning. Luz has presented at the international Critical Media Literacy Conference of the Americas, sharing research on students’ perceptions of nature and sustainability through photovoice.

Deeply passionate about equitable access to green space, Luz is committed to creating environments where all young people can thrive outdoors. Outside of work, she enjoys capturing everyday moments on film and rollerskating through the city.

Nafis Khan

Administrative Coordinator

Bio

Nafis Khan became the Administrative Coordinator in 2025 after leading recruitment, supervision, and organization of Public Health AmeriCorps Members as CS' PlacemakingCorps Coordinator in 2024. He first joined the Concrete Safaris team as a Health Promotion Intern in 2022 through OLA-CUNY after his sophomore year of college in 2022. In November of 2022, Nafis transitioned to becoming the Health Promotion Lead. Nafis earned his B.S in Health Psychology from CUNY Hunter College in 2023 and will begin graduate school to earn his Doctorate of Physical Therapy next year. Outside of work, he enjoys playing sports outdoors and coaching youth AAU basketball.

Savannah Nicholas

Education Coordinator

Bio

Savannah Nicholas has served as the Education Coordinator for Concrete Safaris Outdoor Leadership Academy Summer Youth Employment Program since 2023. Her journey with Concrete Safaris began in 2019, when she joined as an Outdoor Play Intern through the same program. Over the years, she has continued to grow within the organization, taking on impactful roles such as Social and Emotional Learning Ambassador, where she thrives as a dynamic and empathetic leader.

Savannah is currently a senior at Virginia State University, pursuing a major in Mathematics with a minor in Computer Science. She is on track to graduate in May 2026. Beyond her academic and professional commitments, Savannah enjoys painting and staying active through regular workouts.

Directors & Officers

Chair David H. Kaufman, Partner, Morrison Foerster

Treasurer Jerren Holder, CFO, Corporate Client Banking Industries, JPMorgan Chase & Co.

Secretary Christopher T. Consalvo, Director of Government Affairs, CenterLight Healthcare

Fund Development Committee Lead Michael Woolley, Retired Attorney

Mandy DeRoche, Deputy Managing Attorney, Coal Program, Earthjustice

Mac Levine, MPH, Executive Director

Junior Board

Team Lead Julian Schwab, Vice President, Ares Management

Jannah Bradford, Assistant Vice President, M&T Bank

Advisory

Leslie Boden, MSUP, Community Health Planning Consultant

Malisa Mccreedy, Built Environment Program Manager, Blue Zones

Perry Sheffield, MD, MPH, Assistant Professor, Departments of Pediatrics and Preventative Medicine, Icahn School of Medicine at Mount Sinai