[8] Kennedy started her W-League career playing for Sydney FC in the 2010–11 season, where she featured in 3 games.

The following year, Kennedy switched clubs and joined the Newcastle Jets in the 2011–12 W-League before returning to Sydney FC in the 2012–13 season.

Kennedy played every minute of Western New York's two playoff games, as the Flash won the 2016 NWSL Championship.

In the final game of the regular season on 30 September, Kennedy scored the game-winning goal on a free kick in stoppage time.

This win allowed Orlando to finish the regular season in 3rd place and qualify for the playoffs for the first time in club history.

In the 2018 NWSL season, Kennedy appeared in 20 games and scored 2 goals; however, Orlando could not repeat their success of 2017 and finished outside the playoffs.

[20] On 16 February 2019 Kennedy won her third W-league Championship title with a 4–2 win over Perth Glory in the grand final.

[24] Upon the expiration of her loan and NWSL contract in December 2020, Kennedy opted to remain in England and sign permanently with Tottenham until the end of the season.

[26] At the end of August 2021, Kennedy signed a two-year deal with Manchester City, joining national team-mate Hayley Raso.

[29][30] Kennedy signed a one-year deal, plus an option for an extra year, with Angel City FC in the NWSL on 21 January 2025.

[34] Kennedy was part of the Matildas squad that won the 2017 Tournament of Nations and defeated the United States for the first time ever.

In the Round of 16 tie against Norway, Kennedy received a straight red card in the 104th minute of extra-time for a DOGSO foul on Lisa-Marie Utland.