She earned her first cap for the national team on February 9 in a friendly against Scotland. After scoring the first two goals of the match playing as a right midfielder, she provided the assist on the United States’ third goal. Press is only the third woman to score two goals on her first match for the U.S. national team following Cindy Parlow Cone in 1996 and Sherrill Kester in 2000. The U.S. defeated Scotland 4–1 and Press was named Budweiser Woman of the Match. Four days later, she scored another goal during her second cap, helping the U.S. defeat Scotland 2–0. No other American woman has scored three goals in her first two games. Press’ third cap for the national team occurred at the 2013 Algarve Cup during the team’s first group stage match against Iceland on March 6, 2013. Press subbed in during the 64th minute for Carli Lloyd and the U.S. defeated Iceland 3–0. During the team’s next group stage match on March 8, 2013, Press scored the fourth goal in a commanding 5–0 win over China. With the goal against China, Press became the fifth women’s national team player to score at least four goals in her first four matches. She earned two additional caps at the Algarve during the knockout stage match against Sweden led by former United States coach, Pia Sundhage, and started in the final against Germany. The United States took first at the 2013 Algarve Cup with a 2–0 win over Germany. Press finished her first year with the senior national team with eight goals in 12 matches.

As a two-year team captain and four-year starter of her high school’s soccer team, Press led Chadwick to two Southern Section Division IV titles. She also lettered in track and tennis. In 2006, she was named NSCAA High School All-American and Parade Magazine All-American. During her high school career, she scored 128 goals, including 38 her junior year alone (a school record). She was named Southern Section Division IV Offensive Player of the Year twice and was a four-time Prep League Offensive MVP.

In her senior year, Press was the recipient of the 2010 Hermann Trophy for being the nation’s top college soccer player. This marked the second consecutive win for a Stanford player following Kelley O’Hara in 2009. Press led the nation in both goals and points, while the club obtained a 23–1–2 record overall. Their only loss in 2010 came in the last match of the season in the College Cup final, which was Stanford’s second consecutive runner-up finish. Press was also named Soccer America Player of the Year, Pac-10 Player of the Year, and earned All-Pac-10 first team and National Soccer Coaches Association of America (NSCAA) first-team All-American honors. She displayed academic proficiency as well, receiving Academic All-America honors and winning the Pac-10’s Scholar-Athlete of the Year for soccer.

Press was drafted to the Washington Freedom as the fourth overall pick in the 2011 WPS Draft. Under new ownership, the team moved to Florida and was renamed magicJack. She scored her first goal in the 64th minute of magicJack’s 2–0 victory over the Atlanta Beat in May. Of the goal, Press said, “It was so good to finish. Being a forward, we go into every game thinking our job is to score, so it’s nice to finally get that accomplished.” During a 4–0 win against the Boston Breakers in July, Press scored her first hat trick in a professional match. After losing in the semifinal of the playoffs, she was awarded the U.S. Soccer Federation’s Rookie of the Year award in part for being the first-ever rookie to have a hat trick. Press finished the season having started in 16 of the 19 games in which she appeared for magicJack. Her eight goals ranked third in the league. During the offseason, Press signed with the Atlanta Beat; however, the league suspended operations before the season began.

After Women’s Professional Soccer folded in early 2012, Press signed a new professional contract with Kopparbergs/Göteborg FC in the Damallsvenskan, the top division league in Sweden. Her first game with Göteborg was a 2012–13 UEFA Women’s Champions League quarterfinal match against Arsenal that ended in a 3–0 loss.

In early 2013, Press signed with Damallsvenskan champions, Tyresö FF, in Stockholm. For the second consecutive season, she scored a goal in her regular season debut. Press scored four goals in a 10–2 win over Sunnanå SK. During the team’s next match, she scored two goals helping the team defeat Jitex BK 7–0. On June 9, 2013, she scored a hat trick during the squad’s 5–1 win over Kristianstads DFF. After following up with a pair of goals scored in each of Tyresö’s next two matches, Press scored her second and third hat tricks of the season, the second in a 5–0 win over Jitex IK on August 24, and the following in an eventual 8–0 win against Sunnanå IF. During the team’s last match of the regular season, Press scored twice against her former team, Göteborg FC, helping Tyresö win 4–1.

Press finished the season as the top scorer in the league with 23 goals, becoming the first American to do so in the history of the Damallsvenskan. Tyresö finished second during the regular season with a 14–6–2 record and thus qualified for the 2014–15 UEFA Women’s Champions League. In October, Press scored Tyresö’s only two goals during the 2013–14 UEFA Women’s Champions League’s Round of 32 match, securing a 2–1 aggregate win over French side Paris Saint-Germain Féminines, and sending her team to the Round of 16. In 2013, she scored three times in the Svenska Cupen and nine times in the 2013–14 UEFA Women’s Champions League competitions, for a total goal tally of 37. Her nine goals scored in the Champions League helped lift the team to the 2014 UEFA Women’s Champions League Final where they lost 4–3 to VfL Wolfsburg.

In January 2014, the Chicago Red Stars announced that Press would be joining their roster for the 2014 season following the conclusion of her time with Tyresö in the 2013–14 Champions League. After Press joined the team in late May (two months into the 2014 NWSL season), she scored a team-high of six goals while playing in only 12 matches and was awarded the team’s Golden Boot. During a match on July 4 against reigning champions Portland Thorns FC at Providence Park, she scored two goals in the last fifteen minutes to equalize the score, after being down 2–0 at halftime. On August 16, she scored another brace with goals in the 17th and 60th minutes helping Chicago draw 3–3 against Western New York Flash. Chicago finished fifth during the regular season with a 9–7–8 record. Press was named to the league’s second XI team by players, coaches, and media.

Press scored a career-high 11 goals (and ranked third-best on the national team) in 2014. During a group stage match against Argentina at the 2014 International Tournament of Brasília, she scored four goals helping the U.S. win 7–0, and qualify for the championship game. Earlier in the year, she scored a goal against Russia in a friendly on February 8, 2014 and again on February 13, 2014. She was selected by national team head coach Tom Sermanni to play at the 2014 Algarve Cup. In October, Press featured in the 2014 CONCACAF Women’s Championship where the team won the tournament.

Press has appeared in several advertisements and promotional pieces for Nike. In 2014, she was featured in a promo for Wheaties. In May 2015, she starred in television commercials for Coppertone. She became a brand ambassador for nutritional product manufacturer Genesis Today in February 2016. In January 2018, she partnered with Hydrive Energy Water.

Press returned to the Chicago Red Stars for the 2015 season. During the team’s first home match against Seattle Reign FC, she scored a brace and assisted a goal scored by Jen Hoy, resulting in a 3–2 win. She was subsequently named the league’s NWSL Player of the Week for week two of the season. On April 25, Press scored two early goals in a drawn match against Portland. At the end of April, having recorded four goals and one assist, Press was the league’s goal leader and was named NWSL Player of the Month. Press missed the next eight games due to her participation in the 2015 FIFA Women’s World Cup. After returning, she scored four goals in a three-game span, including a brace in the Red Stars’ 2–2 draw with FC Kansas City on August 1.

Press’ likeness appeared on The Simpsons along with teammates Alex Morgan and Abby Wambach in May 2015. The same year, she starred in the short film, An Equal Playing Field. She has been featured in a number of magazines including Self, Howler, Shape, Darling Magazine and Glamour. In 2015, she was featured on the covers of Sports Illustrated and Yoga Digest. In 2016, Press posed nude for the ESPN’s annual The Body Issue magazine.

Press was featured with her national teammates in the EA Sports’ FIFA video game series in FIFA 16, the first time women players were included in the game. In October 2015, she was announced as a host for FOX Sports’ @The Buzzer and led a Chicago Cubs crowd in singing “Take Me Out to the Ballgame” along with teammates Julie Ertz and Lori Chalupny.

During the 2016 season, Press was named captain and tallied eight goals in 14 games. She scored a goal in the NWSL Playoffs, though the Red Stars were eliminated after a 2–1 loss to the Washington Spirit in extra time.

Press was one of two U.S. Players to appear in all 25 games in 2016. She finished 2016 with 12 goals, which was the third straight year she recorded double-figure goals and was her best goal-scoring record on the team. She became the fifth player in team history to score double-figure goals for three consecutive years, joining Mia Hamm, Abby Wambach, Tiffeny Milbrett, and Carli Lloyd in the team record books.

Press captained the team for a second season in 2017. She was the top scorer on the team with 11 goals and the fourth highest scorer in the league. Chicago finished in fourth place during the regular season with an 11–7–6 record, securing a berth to the playoffs. The team was defeated by regular season winners North Carolina Courage 1–0 during the semi-finals. Press was named to the NWSL Best XI at the end of the season.

In 2017 Press once again appeared in every game for the United States and was one of only three players to do so. She scored the only goal in a 1–0 win over Norway in a June friendly. At the 2017 Tournament of Nations held in three different venues in California and Washington, Press scored a goal in the 80th minute against Brazil to lift the U.S. score deficit to 3–2. Five minutes later, she provided the assist to Megan Rapinoe’s equalizer. With an additional goal from Julie Ertz, the team turned the game around for a 4–3 win. She finished 2017 with three goals and three assists.

On January 18, 2018, Press was traded to the Houston Dash as part a three-team trade which also included Carli Lloyd and Samantha Kerr. On March 10, the Dash were informed that Press would not be joining the club and had multiple offers abroad in Sweden.

In March 2018, Press signed a three-month contract with her former club Kopparbergs/Göteborg FC, though the Dash still held her NWSL rights. After scoring four goals in three games, Press was named Damallsvenskan Player of the Month for April. In May, she scored a brace in the team’s 3–1 win against IF Limhamn Bunkeflo. On June 19, the team announced an agreement with NWSL expansion club, Utah Royals FC, to end her contract early so she could join the Royals for the remainder of the 2018 season.

Press was named to the roster for the 2018 SheBelieves Cup in February. The U.S. won the tournament for the second time. After she was traded against her wishes to the Houston Dash, Press declined to join the team and was reportedly considering multiple offers from Swedish clubs. She was subsequently left off the U.S roster for a set of friendlies against Mexico in April 2018, with head coach Jill Ellis stating: “We’ve had several conversations and [Press] understands our expectations are that a consistent training and match environment for a professional is an important factor for selection into women’s national team rosters…I am certain that once Christen transitions to a new team, she will embrace being back on the pitch and will help her team be successful.”

Press began the 2019 NWSL season assisting Lo’eau LaBonta’s goal in a 1–0 over the Washington Spirit in Utah’s season opener. The following week, Press scored the only goal in 1–0 Royals victory over the Orlando Pride. Press was named to the NWSL Team of the Month for April. She recorded a goal or assist in her first five games of the season but, due to her participation in the 2019 Women’s World Cup and subsequent Victory Tour, missed 11 Utah games during the season. Press was named NWSL Player of the Week for Week 17 and later named NWSL Player of the Month for August, her second player of the month award. Press finished second on the team in scoring with 8 goals and was named to the end of season NWSL Best XI, her fourth time being named to the Best XI.

In January 2019, Press scored the only goal in a 1–0 victory over Spain in a friendly in Alicante. At the 2019 SheBelieves Cup she assisted on Alex Morgan’s goal, one minute after entering the game. A month later in a friendly against Belgium, Press recorded 3 assists in a 6–0 victory.

On May 2, 2019 Press was named to the final 23–player roster for the 2019 FIFA Women’s World Cup—this was her second time to play for the Cup.

On November 7, 2019 Press became the 12th player in USWNT history to score 50 international goals. Her 50th goal occurred in the 28th minute of a friendly against Sweden. The United States won 3-2 and Press also recorded an assist in the game. Press finished 2019 with 5 goals and 12 assists. Her 12 assists lead the team, she was also the only member of the USWNT to appear in all 24 games in 2019.

With the 2020 season disrupted by the COVID-19 pandemic, Press elected not to participate in the 2020 NWSL Challenge Cup.

On November 12, 2020, having left Press unprotected, Utah lost her NWSL rights to Racing Louisville FC during the 2020 NWSL Expansion Draft.

On September 9, 2020, Manchester United announced it had signed Press, along with her national team teammate Tobin Heath, to one-year contracts. She made her debut on October 4 as a 77th minute substitute in a 3–0 victory over Brighton & Hove Albion. She scored her first goal for the club on October 18 as part of a 4–2 WSL victory away to West Ham United.