[19][21] She played for local boys' teams Pearson Juniors under-7s, and then Samba Stars[22] – both coached by the father of her primary school best friend, who initially took her along[20] – until she turned eleven.

[44] She played for the under-17 team in the 2013 FA Girls' Youth Cup final against Arsenal, narrowly missing an opening goal, with Blackburn eventually losing the match.

[42][47] Blackburn Rovers later saw recognition for developing midfielders in women's football, having successively produced Walsh, Stanway and Ella Toone: important players for England in 2022 and 2023.

She was uncertain about the opportunity, but her mother encouraged her to attend the trials; before the session was complete, first team coach Nick Cushing, who had gone as an observer, wanted to sign Walsh to the main squad as their holding midfielder.

[95] Early in the 2018–19 season, Walsh captained City for the away leg of their Champions League Round of 32 tie against Atlético Madrid, drawing 1–1 when away goals were an advantage.

[96] City lost the return fixture 0–2 to be knocked out in the Round of 32 for the first time,[97] the start of a five-season pattern of exiting the Champions League by Spanish opposition[98] that helped prompt Walsh to leave the club (for Spain) in 2022.

[110][111] At the end of the year, she placed joint-ninth (with Jennifer Hermoso) on the International Federation of Football History & Statistics (IFFHS) ranking of the Women's World Best Playmaker.

City lost 0–2,[118] with Walsh later reflecting that her conduct came from being a fan of her team and frustrated that their rivals were winning, and that she had since come to practice more control over her support than she displayed in the match.

[121] 90min wrote that this was somewhat surprising to onlookers – considering Walsh's long tenure, prior transfer request, and Cushing recently leaving the club – but that City and its fans would welcome her decision.

[123] Said by the Manchester Evening News to be growing in confidence in her role, the newspaper considered Walsh the key player for City ahead of their attempt to win the league for the first time since their successful 2016 campaign, after being retroactively demoted to second place due to points per game calculations in the previous season.

[128] Coach Gareth Taylor (who replaced Cushing as manager in 2020) joked after the match that Walsh "was getting a bit sick of everyone else missing chances", adding that she did not need to score goals as the club recognised the importance of her role.

[137] She first returned to playing in October 2021 and,[138] in November, scored a powerful strike against Leicester from the edge of the box to put City ahead,[139] which was shortlisted for the WSL goal of the month.

[174] Walsh said that while "the price tag [is] a nice feeling", she prefers not to be the centre of attention;[160] she said she felt honoured to join Barcelona, pointing to the team's level and that "it is such a historic club, and [...] more than that, it is a culture.

[198][199] Walsh was differential for Barcelona in the away leg victory of their Champions League semi-final tie against Chelsea, playing what Sport said was her best game for the club yet, in which "she showed that version of pivot that characterises the azulgrana style.

Walsh again started in the Champions League final, making vital recoveries as they defeated Lyon 2–0,[213] her performance called a recital by Maria Tikas.

[228] Their second 2024–25 league game was played on WSL deadline day, and Walsh "silenced the rumours" of a last-minute transfer when she started the match and provided the assist for Caroline Graham Hansen's opening goal.

[238] After this, with Putellas back to full fitness, Walsh was more often sidelined by new head coach Pere Romeu, who struggled to manage a four-player midfield and preferred a more attack-minded formation.

[21] She served as under-19 captain for some of their appearances at the March 2015 La Manga Tournament in Spain,[279] and wore the armband again after returning from injury for 2016 U19 Euro preparation matches in September and November 2015.

[285][286] In November 2017, Walsh was called up to the senior England squad for the first time, along with Williamson, by interim coach Marley for the 2019 FIFA Women's World Cup qualification campaign.

[293][294] During the campaign she was one of two senior Lionesses (along with eventual winner Beth Mead) to be nominated for the 2018 England Women's International Young Player of the Year award.

[308] In the opening games of the World Cup, Walsh did not play to her usual standards, but she continued to be picked to start, with Neville having faith in her game and her development; England fans were heavily critical of her continued selection after the early weaker showing, but she performed well in the semi-final against the United States, which England lost:[43] she provided two long passes that produced Ellen White goals (one was disallowed) and sent a narrowly-saved powerful strike at goal from 25 yards herself.

[310][20][160] Still struggling in January 2020,[311] Walsh was encouraged by Neville and England's then-head of performance Dawn Scott to "address her lifestyle habits" so that she could develop further and be able to focus on marginal gains.

[28] Walsh repeated the sentiment in a press conference after she was voted player of the match in England's first game after the Euro,[350][351][352] a 2–0 win over Austria that saw them qualify for the 2023 World Cup.

[365][366] She was more commanding and influential in the quarter- and semi-final wins over Colombia and Australia,[367][368] performing reliably to help the Lionesses reach a World Cup final for the first time.

[393] In England's final group game, which saw them qualify, the team had found ways to overcome the marking of Walsh, including using her as a left-sided centre-back for parts of the match.

As the game went to extra time, Walsh again opened striking, with a strong shot from distance tipped over the top of the net by a fingertip save in the 96th minute.

[a 9] With her frequent scans of the field, Walsh will make herself open to receive the ball in a good position to retain possession or to use her first touch (which she will often take with the outside of her foot) to get away from pressure.

[a 11][321] She also provides defensive cover, shadowing opposition players to disrupt their play when they have possession[413][401] and to create space for her teammates to progress in attack when they are on the ball.

[8][401] Walsh is effective in her midfield defensive actions[8][401] – she is reliable for interceptions and recovering loose ball situations,[8][401] and success when tackling,[413] which has become a more defining part of her game[417][425] since 2022[423] – as well as supporting the back line.

[41][427] Footage of Walsh in a 2022 England training session, in which she scored a solo goal after creatively evading the members of the opposition five-a-side team, was also shared widely,[426][429] particularly as it coincided with the high-profile Barcelona pursuit of her signing.