After his mother, Meredith Scanlon went to prison and his father, Lewis Scanlon took off, Ryder had suffered a momentary nervous breakdown and allegedly set the Scanlon house on fire while burning 20 of his father's suits in the driveway (referenced in Pilot).
However, since coming into Mel's custody, he has shown no further evidence of pyromania or other destructive tendencies.
Out of the two Scanlon children, Ryder is the one who looks up to Joe the most and frequently asks for his advice. Because he lacks confidence, he frequently ends up seeking out help and advice from other characters (with mixed results)
Holly was Ryder's manipulative, controlling girlfriend, and he did everything to try to make her happy. During a School field trip in the third season, Ryder got suspended for smoking which causes Holly to break up with him (plus, Holly also cheated on him with Tim Logan.)
Whilst being home schooled, after being suspended for using drugs on a school trip, he meets another home schooled boy from the neighbourhood (for 1 episode only).
After upsetting him for calling him a nerd, Ryder meets the boy's sister, Kira. She soon becomes his girlfriend. Although the break up between Kira & Ryder isn't discussed, Ryder then starts to date a single mother, Stella.
They soon break up due to Stella finding out that Ryder wanted to break up a few days before a school dance after reading a break up letter that Ryder wrote in preparation. However, before Stella read the letter Ryder had changed his mind about the break up. Stella still broke up with him anyway.
In 2015, Ryder enlisted in the Navy.