Agosta played for the Canada women's national ice hockey team and is a three-time gold medallist from the 2006, 2010 and 2014 Winter Olympics.

During the 2006–07 season at Mercyhurst College in NCAA Division I hockey, Agosta was the first freshman named as a finalist for the Patty Kazmaier Award.

[2] She later competed for the AA Windsor Wildcats[permanent dead link‍] of the Ontario Provincial Women's Hockey League.

On February 4, 2011, Meghan Agosta became the all-time leading scorer in NCAA women's hockey history with three goals and one assist in Mercyhurst College's 6–2 win over Wayne State.

[7] Wayne State goalie DeLayne Brian was the goaltender in net when Agosta broke the record.

[10] In 2011, Agosta was named CHA Player of the Year as well as a First Team All-CHA selection, marking the fourth time in her career she captured both accolades.

With the hat trick, she topped 300 points for her NCAA career as the Lakers defeated Syracuse 5–4 and captured its ninth straight College Hockey America title.

[13] In the 2011–12 season, Stars forward Agosta won the Angela James Bowl while breaking the league's single-season scoring record.

Her brother Jeric received a full scholarship to play hockey at the University of Nebraska Omaha.

[4] On August 31, 2012, Agosta married Marco Marciano, the Canadian national women's team goaltending and video coach.

In fall 2014, Agosta took a break from hockey and joined the Vancouver Police Department as a probationary constable.

She took a year leave from the Vancouver Police Department to train and play with the Canadian national team before the 2018 Olympics.

[30] In 2020 she took part in the televised reality competition show "Battle of Blades" with figure skater Andrew Poje.