2009-10: Ryan Hartman skated for the Chicago Mission U16 team in Illinois. In 38 games he scored 25 goals with 19 assists and had 64 penalty minutes. He committed to playing college hockey at Miami University in 2013-14 and was drafted by Plymouth in the fifth round (95th overall) of the 2010 OHL Priority Draft.
2010-11: Hartman was selected for the USA National Team Development program in Ann Arbor and played four games with the NDTP's U18 team while spending most of the year with the U17 squad. He had 1 assist and 4 penalty minutes in four games with the U18 team. Hartman was the U17 team's leading scorer in regular season play – scoring 22 goals with 12 assists – and had 88 penalty minutes in 52 games. In international play he scored 2 goals with 2 assists in the 2010 Four Nations Cup and had 4 goals and 2 assists in six games as the USA finished second in the 2011 U17 World Hockey Challenge. Hartman scored 3 goals in 3 games as the USA U17 team captured the 2011 U18 Vlad Dzurilla Tournament in Slovakia.
2011-12: Hartman returned to Ann Arbor for a second season, finishing as the U18 team's second-leading scorer, and won a gold medal with Team USA at the 2012 U18 World Junior Championship. He scored 16 goals with 25 assists and had a team-high 136 penalty minutes in 59 games. In six games at the U18 WJC he scored 2 goals with 4 assists and was plus-nine with 22 penalty minutes. Hartman de-committed to playing college hockey at Miami and in May signed to play with the OHL's Plymouth Whalers in 2012-13.
2012-13: Hartman was the third-leading scorer for Plymouth despite missing 12 games and was part of the USA team that won a gold medal at the 2013 U20 World Junior Championship. He scored 23 goals with 37 assists and was plus-29 while leading the Whalers with 120 penalty minutes. Plymouth reached the second round in the playoffs before falling to London. Hartman scored 4 goals with 2 assists and was plus-four with 16 penalty minutes in nine playoff games. In seven games at the WJC he scored 2 goals with 1 assist and was plus-four with 16 penalty minutes. Hartman was ranked 16th amongst North American skaters in Central Scouting's final rankings prior to the 2013 NHL Draft.
At 5’11, 190 pounds, Hartman’s size is not exactly eye-popping, but his ability to excel at all facets of the game most certainly does. Hartman is a tough 5’11 and is willing to throw his body around. He finds his way into the gritty areas of the ice and has solid enough hands to convert a few opportunities. He’s also played both center and the wing, making him a versatile player with an all-around game.
Hartman will return to the Plymouth Whalers of the OHL for the 2013-14 season. He is slated to be back from injury for the start of the junior season, but the early-summer shoulder surgery was the likely reasoning behind him not being invited to Team USA's Evaluation Camp. After a strong performance for the team in 2013, a strong start to his year with the Whalers could very well earn him a spot in December's selection camp.