In one instance, Martinez acknowledged he angrily grabbed a player.
Martinez was in his first year as a professional coach this year. He sat in the dugout during Sunday's 3-2 win over the Pittsburgh Pirates, then met with Marlins officials and resigned.
"I want to apologize to the Marlins organization for my behavior," Martinez said. "I have made some comments to certain players at certain times that I thought was more constructive criticism. Obviously, they didn't feel that way, and it kind of backfired on me."
Martinez said he once touched a player in anger, grabbing rookie Derek Dietrich by the jersey in the batting cage early this season. Dietrich, demoted last Monday to Double-A Jacksonville, was among the players to complain.
Martinez said he offered to resign earlier, but team owner Jeffrey Loria wanted him to stay on the job. When the complaints by players became public in a story Sunday by the Miami Herald, Martinez became certain he should resign.
"It has been building for a few days," he said. "I didn't know this was going to come out publicly. When this came out, I thought it was the right thing to do."
Marlins minor league field coordinator John Pierson will become interim hitting coach. First-year manager Mike Redmond said everyone in the organization was disappointed with the outcome of Martinez' brief tenure.
"Coaching's tough," Redmond said. "Going from a player to a coach is hard, and part of the grind is learning how to deal with different situations with different players and different personalities. All that stuff is a challenge. Some people can do it, and some people can't."
The young Marlins rank last in the majors in runs, home runs, batting and slugging, and the 45-year-old Martinez said he became frustrated as players struggled.
"I just thought with some young players you needed to be a little firmer and try to get them on the right track," he said. "I probably used some four-letter words. I thought I was doing the right thing. Obviously, I wasn't."
Martinez batted .271 with 339 home runs, and he was a four-time World Series champion with the New York Yankees. He had a three-year contract with the Marlins but said because he resigned, he'll receive no buyout.
He declined to speculate on whether he'll coach again.
"I don't know long term how it's going to affect me," he said. "Right now I'm disappointed in myself. I'm embarrassed. Right now I'm not worried about the future. I just want to make sure my family is OK."