2010-11: Alex Lintuniemi played 27 games for the HIFK U18 team in Helsinki as a 15-year-old and appeared in seven games with the Finland U16 team. He scored 3 goals with 12 assists and had 8 penalty minutes in B juniors play. Lintuniemi had no points and 4 penalty minutes with the Finland U16 squad.
2011-12: Lintuniemi moved from HIFK to cross-town rival Jokerit — appearing in three games with the club’s U20 team and winning a B junior championship with the U18 team. He was +1 with 1 assist with the Jokerit U20 team. Lintuniemi scored 4 goals with 17 assists and had 24 penalty minutes in 37 games for the Jokerit B junior team during the regular season and scored 2 goals with 5 assists and 8 penalty minutes in 11 playoff games.
2012-13: Lintuniemi made his pro hockey debut — playing with Kiekko-Vantaa in Mestis — and was a team captain for the Jokerit U20 team as a 17-year-old. He also skated for the Jokerit U18 team in the B juniors playoffs and represented Finland in the 2013 U18 World Junior Championship. He was minus-3 with 1 goal, 2 assists and 6 penalty minutes in 11 Mestis games. Lintuniemi scored 4 goals with 10 assists and was minus-6 with 76 penalty minutes in 38 games for the Jokerit A junior team. He scored 4 goals with 4 assists and 6 penalty minutes in 10 games during the B juniors playoffs and was +3 with 2 assists and 8 penalty minutes in seven games as Finland won a bronze medal at the WJC. Lintuniemi was the second player taken in the 2013 CHL Import Draft when he was selected by the Ottawa 67′s.
2013-14: Lintuniemi was one of three players to skate in all 68 games for the Ottawa 67s in his first season in the Ontario Hockey League. He scored 4 goals with 17 assists and had 26 penalty minutes while finishing minus-38 on a team that finished last in the OHL’s East Division. Ranked 187th amongst North American skaters in Central Scouting’s final rankings prior to the 2014 NHL Draft he was selected by Los Angeles in the second round (60th overall).