MacKenzie followed his father — a former Moreno Valley Fire Department captain — into firefighting.
His family and friends said he loved fighting wildfires because "it was a way to see the most beautiful country in America."
MacKenzie spent four seasons working for a ski resort in southern California's San Bernardino Mountains. He also served on a helicopter crew for the U.S. Bureau of Land Management and as a Hotshot in the San Bernardino National Forest.
He applied for the Granite Mountain crew at the invitation of one of his former captains, Aaron Stevens.
His family said he was loved by everyone he knew and collected friendships like people collected shot glasses.
ERIC MARSH: HOOKED ON FIREFIGHTING
A native of North Carolina's Blue Ridge Mountains, Eric Marsh was known for his cool head and "Southern gentleman" demeanor, even in the hairiest of situations
Other firefighting teams would rib him about his laid-back manner.
"Eric had this deep soothing voice that no matter how amped everyone around him got, he was able to stay real mellow. We'd be like, 'Out west we gotta move a little faster, talk a little faster, Eric,'" said Marsh's friend, Patrick Moore, superintendent of another Hotshot crew.
Marsh, 43, was an avid mountain biker who became hooked on firefighting while studying biology at Appalachian State University. Marsh built the Granite Mountain Hotshots from nothing — and died trying to protect the crew that friends say constituted his life's work.
"Eric was 90 percent a Granite Mountain Hotshot, and the 10 percent was left for us," his wife Amanda said at a July Fourth carnival after his death.