The son of Maryland offensive coordinator Mike Locksley, he said his decision came down to Florida State or Texas. He had the Terps in his top three, but said he recently dropped them from consideration.
Locksley, 6 feet 5 and 200 pounds, said the decision came down to his comfort level with coach at Florida State.
"I had been down there three times during the process and I built a real strong relationship with those coaches and in terms of opportunity and development, the coaching staff is top notch in all those areas," he said. "I felt as though it was the best school to help me make my dream come true in terms of making it to the NFL."
Locksley is rated a 4-star quarterback and the No. 1 player in Maryland in the Class of 2015 by the recruiting website Rivals.com.
He had more than 20 offers, according to Rivals, from programs such as Alabama, Auburn, Georgia, Michigan State, Ohio State, Oregon, Texas, UCLA, Wisconsin and Maryland, which made him an offer before any other program.
"They kind of were my dark horse throughout this whole process," Locksley said of the Terps. "They were a school I felt could, out of nowhere, just pop up, but we kind of decided together that it was real hard to play for your dad, especially at the level that he's at and [Maryland] being a strong program and a Division I program. It's much tougher to do it in college and we decided it was better to go elsewhere and grow myself as my own man."
Last season as a junior, Locksley was an All-Metro second-team selection after running for 795 yards and 14 touchdowns and passing for 875 yards and five touchdowns. No. 2 Gilman finished 7-3 overall and 5-1 in the Maryland Interscholastic Athletic Association A Conference, losing only to No. 1 McDonogh.
Locksley, who made his only trip to Texas a week and a half ago, finally came to the conclusion Wednesday that Florida State was the best fit for him.
"I've been flipping back and forth the past couple days this week trying to make the decision," he said. "But yesterday I finally threw out all equations and wanted to see what my gut felt was right, and it was Florida State. I woke up and was real confident in that decision, so I made the call this morning to coach Jimbo [Fisher, the Florida State coach]."
Gilman coach Biff Poggi said Locksley has high expectations, and Florida State gives him a great opportunity to grow into them.
"Jimbo Fisher's record of developing quarterbacks is pretty impressive," Poggi said. "Going all the way back to LSU with JaMarcus Russell then at Florida State with EJ Manuel and now the Heisman Trophy winner (Jameis Winston).
"Kai was very interested in that and they were very, very interested in Kai. They really like him as a player. I got a call from coach Fisher and they are recruiting him to be a quarterback and they really think he can be a good one."
Locksley had originally planned to make his announcement on the first game day for Gilman, but a couple weeks ago, he set a new goal to decide before Greyhounds training camp opens Wednesday.
"As the process got harder and as the decision got harder, I just wanted to get it out of the way before camp started, so I could put my whole focus on my team, give them all of me."
The Greyhounds are known as a power-running team, but Poggi said they will air it out a bit more this season with Locksley's arm and some capable receivers.
"I'm glad he's finally taken off the reins," Locksley said with a laugh.
Locksley plans to major in broadcasting, so if he doesn't make the NFL he can stay connected to the sport by talking about it.
He is the second local player to commit to Florida State in four months following All-Metro offensive lineman David Robbins from Glenelg, who committed in April.