The 27-year-old left-back has become a key part of Everton's defensive set-up and says the decision reflects both his comfort at the club and his belief in the direction the team is heading.
"I feel excited to sign this new contract - very excited and proud," Mykolenko told Everton TV.
He also highlighted the impact of senior figures when he first arrived, especially captain Seamus Coleman.
"I remember the first message I received from Seamus when I signed in 2022. I remember reading it and thanking him for welcoming me. He gave me that confidence immediately that I'm in a proper family here," he said.
Mykolenko admitted Everton have faced difficult spells since his arrival, but believes the club has grown stronger through those challenges.
"In the first few years of my time here we were struggling, but our team, as a family, every person in the building gave everything to get through it. What we have now is stronger and we are getting better every season," he added.
The defender also praised manager David Moyes for his influence since taking charge, saying the Scot has helped create structure and freedom within the squad.
"Since the manager came in, we are building up. He's a very good person and gave me freedom on the pitch," Mykolenko said.
Looking ahead, he set his sights on improvement in the Premier League and long-term success.
"Next season, we want to finish much higher. I like realistic dreams - winning a trophy or maybe a European trophy," he said.
