Born in Fort St. John, British Columbia, Nedohin's family moved to Alberta.
Nedohin won her first and only Alberta provincial junior curling title in 1996. This earned her, and her Grande Prairie rink of third Carmen Whyte, second Kristie Moore and lead Terelyn Bloor the right to represent Alberta at the 1996 Canadian Junior Curling Championships in Edmonton. The team finished the round robin with a 9-3 record, tied for first with Nova Scotia's Meredith Doyle. By virtue of beating Doyle in the round robin, Nedohin earned a bye to the final where she met Saskatchewan's Cindy Street who beat Doyle in the semi-final. Nedohin beat Street 7-5, earning her rink a berth in the 1996 World Junior Curling Championships in Red Deer, Alberta.
At the 1996 World Juniors, the team placed third after the round robin, with a 7-2 record, behind Sweden's Margaretha Lindahl and Swtizerland's Nadja Heuer. However, they beat Switzerland in the semi-final, 6-4, and then beat 4th place Scotland's Julia Ewart 7-6 in the final, earning the team the gold medal.
After Juniors, Nedohin joined the Cathy Borst (King) rink as the team's third. As a member of the Borst rink, Nedohin won her first provincial title in 1997. This qualified the team for the 1997 Scott Tournament of Hearts, representing Alberta. The team finished the round robin in a three-way tie for 2nd place with a 7-4 record. However, the rink lost the 3 vs. 4 page playoff game against Newfoundland's Laura Phillips.
The rink won their second provincial title in 1998, qualifying them for the 1998 Scott Tournament of Hearts This time, the team finished the round robin in first place, with a 10-1 record. The rink defeated Ontario's Anne Merklinger twice to win the championship. In both games they beat Merklinger 7-6, both going into extra ends. The win earned the team a trip to the 1998 Ford World Curling Championships in Kamloops, British Columbia.
At the 1998 Worlds, the rink finished the round robin in a three-way tie for second with a record of 6-3. In their semi-final match up, the team lost to the first place Sweden team, skipped by Elisabet Gustafson by a score of 8-7. The team then went on to beat Norway's Dordi Nordby 10-2 for the bronze medal.
By virtue of winning the 1998 Hearts, the team got to represent Team Canada at the 1999 Scott Tournament of Hearts, as defending champions. The rink had another winning record at the event, finishing the round robin in third place, tied with Saskatchewan's Cindy Street at a record of 7-4. The rink beat Street 10-4 in the 3 vs. 4 game, then beat Manitoba's Connie Laliberte 10-4 in the semi-final. This put the team in the final against Nova Scotia's Colleen Jones, which they lost, 6-4.
In 1999, Nedohin left the King rink, to form her own rink of Carmen Barrack, Kristie Moore and Rona McGregor. In their first season together, the team won the Alberta provincial championship, Nedohin's third. The team represented Alberta at the 2000 Scott Tournament of Hearts, but did not make the playoffs. The team finished the event with a 6-5 record.
After failing to win another provincial title, the team broke apart in 2002, and Nedohin joined up with Atina Johnston whom she played three seasons for. In 2005, she joined the Deb Santos rink as her third, and then in 2007 she joined up with former teammate Kristie Moore as her third. The following year, the team juggled its lineup, and Nedohin was once again a skip, with Moore becoming the team's second. Beth Iskiw would throw third stones and Pamela Appelman remained as the team's lead.
The team's new line up earned the team a spot at the 2009 Alberta Scotties Tournament of Hearts, where they lost in the final to Cheryl Bernard. After the season, Moore left the rink and was replaced with Jessica Mair. The rink failed to make the playoffs at the 2010 Alberta Scotties Tournament of Hearts.
In 2010, Nedohin added Nova Scotian Laine Peters as the team's lead. At the 2011 Alberta Scotties Tournament of Hearts, Nedohin lost to Shannon Kleibrink in the final.
The team would have a stellar 2011-12 season. Nedohin went to her first Grand Slam final at the 2011 Manitoba Lotteries Women's Curling Classic, where she lost to fellow Albertan Renée Sonnenberg (a team that included 3 of Nedohin's former teammates). Her rink then went on to win the 2012 Alberta Scotties Tournament of Hearts, giving her another trip to the national championships. At the 2012 Scotties Tournament of Hearts, in Red Deer, the team finished the round robin with a 7-4 record, tied for third with Quebec's Marie-France Larouche. They then beat Larouche 7-4 in the 3 vs. 4 game, and then beat Maniotba's Jennifer Jones 6-5 in the semi-final. In the final, Nedohin won the national title, defeating British Columbia's Kelly Scott 7-6.
Nedohin's 2012 Scotties win qualified her team to represent Canada at the 2012 Ford World Women's Curling Championship in Lethbridge, Alberta. The rink finished the round robin with a 7-4 record, tied for fourth with the United States' Allison Pottinger. Nedohin beat Pottinger in the tie breaker match, qualifying them for the playoffs against Korea's Kim Ji-sun. Nedohin lost to Kim in the 3 vs. 4 match, by a score of 4-3. This put them in the bronze medal game, where Nedohin would face Kim once again. With the bronze on the line this time, Nedohin beat Kim, 9-6, earning Canada a bronze medal.
As winners of the 2012 Scotties, Nedohin would get to skip Team Canada at the 2013 Scotties Tournament of Hearts. Nedohin's rink would not be able to repeat her 2012 performance, as her team would finish 4th, after losing in the bronze medal game to British Columbia's Kelly Scott.
Nedohin would play in the 2013 Canadian Olympic Curling Trials where she would finish with a 3-4 record, missing the playoffs.
In 2015 Heather Nedohin announced she would be stepping back from the game and that Chelsea Carey, formerly of Manitoba, would be taking over her current team.
Nedohin is a stay-at-home mom and a graduate of Grande Prairie Regional College and North Peace High School. Since the spring of 2014 she has been business manager of the Sherwood Park Curling Club, in Sherwood Park, AB.