}}Mark Cyr (portrayed by Jason Ritter) is Amber's favorite English teacher who has a romantic relationship with Sarah. Mark is 12 years younger than Sarah. They have an on-again-off-again relationship. He appears in Seasons 1, 3 and 4.
In Season 1, Mark and Sarah get to know each other and start dating much to the dismay of Sarah's kids Amber Holt and Drew Holt. Sarah decides she is too old for Mark and that it won't work so she breaks up with him.
They get back together in Season 3 after he helps her with her play. In the last episode, at Crosby and Jasmine's wedding, Mark proposes to Sarah. She accepts.
In Season 4, Sarah and Drew move in to Mark's apartment in the episode 6 "I'll Be Right there". In episode 10, Sarah puts Hank Rizzoli before Mark when she lies to Mark so Hank can reconnect with his daughter Ruby
In Season 5 episode 19 "Fraud Alert".Mark runs into Amber on the street and says to tell her mom hi. Soon after he calls Sarah and asks her to lunch. After some small talk Mark tells Sarah that he met someone and is now engaged and he wanted her to hear it from him.