Mark was Ashley's short-term fling shortly after she arrived at Grant. He came up to introduce himself to Ashley in front of Griffin, who told Mark to go away because Ashley "wasn't interested in dating in high school". Ashley said to Griffin that Mark was "slightly tempting".
Later, after Griffin told Mark again to back off, Mark said that he wanted to "marry her (Ashley) and have children with her". He went to the TAG (Teen Abstinence Group) meeting with Griffin, when Grace told them all about having sex with Jack. Mark was afraid that just because he was there with Griffin, people would think he was gay.
Later that night, Griffin and Mark's mom sat in her car together and Griffin explained that Mark was in love with Ashley, and that he (Griffin) wasn't interested in Mark. According to Amy, Mark and Ashley were "makin out on the front porch". He was mentioned by Griffin later in the season, and apparently Ashley had gotten over him, because when Griffin told her that he was going out with someone else, Ashley scoffed and said, "Thank God".