Baxter was crew chief for the No. 99 Toyota that competed in the race with driver Patrick Carpentier.
As Wallace was driving down pit road after the race with his helmet off, Baxter reached into Wallace's car and had pulled Wallace's hair. The incident was caught on Wallace's in-car camera and shown on the ESPN broadcast.
Wallace and Carpentier had been involved in an inicident on the track early in the race.
On Monday, Baxter issued an apology for his actions.
"I'm sorry for what happened after the race on Saturday and I take responsibility for my own actions," Baxter said in a statement. "I was just very frustrated and let my emotions get to me. That was Patrick's last race and we wanted to make it special.