May, who lost assistant coach Aaron Feis and athletic director and wrestling coach Chris Hixon in the shooting, cited the incident as the primary factor for his resignation.
"It's been hard to come to work with everything that's went on," May told the Sun Sentinel on Wednesday. "I miss Aaron Feis every day, and I miss Chris Hixon every day. It's been really hard, and I just needed a change. I needed a change for my soul.
"I will always be grateful for the love and affection the community showed my family. I will always wish nothing but the best for the whole community, Parkland, and definitely Marjory Stoneman Douglas. Want only the best for them."
Feis, who died in the shooting Feb. 14, 2018, shielded students from the attack when a former student armed with a gun opened fire inside the Parkland, Fla., school.
May and other members of the coaching staff left Feis' desk unchanged following his death. May said seeing the reminders on campus in the aftermath of the tragic event pushed him to the point of walking away.
"We've got a cemetery on campus that we have to look at every day, when it comes to the 1200 building," May said. "They know I have to walk in my office and Aaron Feis' desk is there without him, and on the other side Chris Hixon's office is there without him. It's hard. They understand."
May disclosed that assistant coach Quentin Short was named interim coach, according to the Sun Sentinel.
May, 51, has a new coaching opportunity lined up in Fort Myers, Fla., which is closer to his parents. The move hasn't been made official yet, meaning the coach isn't allowed to discuss specifics, according to ESPN.
"I came out of the interview, and my dad asked me what I thought of the school," May said. "I said it was really nice, and he asked if he would be able to come to practice every day. They could have been the worst school in the world and I was going to go, because I can spend time with my dad."
May was head coach of the Eagles for six seasons. He had a 33-26 record during his time at the school. Stoneman Douglas went 5-5 last year and missed the playoffs. They ended their home schedule with a tribute to the victims of the shooting, including the retirement of Feis' No. 73 jersey number.