She held the record for the most weeks at the top of the World Amateur Golf Ranking,[2] and in 2022 became the first – and, to date, only – Irish woman to win on the LPGA Tour.
On 10 September 2005, she won the 10th HSBC British Wee Wonders Championship by 11 shots at the Balgove Course, St Andrews, Scotland, with a finishing round of 61.
[24] On 12 June 2016 at Dún Laoghaire Golf Club, Maguire was part of the Great Britain & Ireland team which defeated the US in an 11½ to 8½ win in the 2016 Curtis Cup.
On 31 July at the Woburn Golf and Country Club in England, Maguire won the Smyth Salver when she finished as the leading amateur at the Ricoh Women's British Open, one of the major championships.
On 17 September, Maguire helped Ireland to a third place bronze medal in the 2016 Espirito Santo Trophy held at Mayakoka El Camaleon Golf Club in Mexico.
[31] Also on 11 May Maguire was selected for the College Sports Information Directors of America Academic All-District III Women's At-Large Team, which recognises the nation's top student-athletes for their combined performances athletically and in the classroom.
[33] On 24 May, Maguire was awarded the 2016-17 GolfStat Cup which is presented to the player with the best scoring average versus par with at least 20 full rounds played during a season.
On 6 July, Maguire represented Great Britain & Ireland in the Vagliano Trophy against Europe, held at Circolo Golf Bogogno, Italy.
On 5 July, Maguire was selected for the Women's Golf Coaches Association (WGCA) All-American Scholars Team for the third year in a row.
On 6 August, at the Kingsbarns Golf Links, Scotland, Maguire made the cut and was runner-up for the Smyth Salver awarded to the leading amateur at the Ricoh Women's British Open, one of the major professional championships, after rounds of 69, 71, 70, 75.
On 15 August 2017, Maguire was awarded the Mark H. McCormack Medal given annually to the number one ranked female amateur golf player in the world.
On 12 September, Maguire began the 2017-2018 College Golf season by winning the Jim West Challenge at The Fazio Course at The Club at Carlton Woods, The Woodlands, Texas, USA.
In December she won the Irish Women's Amateur Golfer of The Year award for the fifth time, equalling the all-time record held by Claire Hourihane.
On 28 February, Maguire was named as an honorary recipient of the ACC Weaver-James-Corrigan postgraduate scholarship, which is awarded to selected student-athletes who intend to pursue a graduate degree following completion of their undergraduate requirements.
On 14 April at the Liz Murphey Collegiate Classic in Athens, Georgia, Maguire broke the all-time ACC record of most even or under par rounds in a college career.
On 13 June, Maguire selected on the CoSIDA Academic All-America® Women's At-Large Team for the second year in a row with a Grade Point Average of 3.94 or A.
In November, Maguire made her professional debut on the Ladies European Tour at the Andalucia Costa Del Sol Open De España Femenino, where she finished in 18th place.
On 1 April, Maguire moved into the top 300 on the world ranking list for the first time as a professional, after finishing fourth in the IOA Championship on the Symetra Tour.
On 17 May, Maguire moved into the top 175 on the world ranking list for the first time as a professional, after winning the Symetra Classic held in Davidson, North Carolina.
On 10 June, Maguire equalled the tournament record lowest round score, with a 65 at the LPGA Mediheal Championship held at the Lake Merced Golf Club, Daly City, California, which meant she was the overnight leader.
On 20 June, Maguire had the biggest payday of her career at the Meijer LPGA Classic at the Blythefield Country Club, Grand Rapids, Michigan.
On 15 August, she achieved her sixth consecutive top 15 place on an LPGA Tour event by finishing 15th in the Trust Golf Women's Scottish Open at Dumbarnie Links, Fife.
[47] On 22 August, she achieved her seventh consecutive top 15 place at an LPGA Tour event by finishing 13th in the 2021 Women's British Open at Carnoustie Golf Links, Angus, Scotland.
[50][51] On 11 November, Maguire broke both the tournament and course records at the Pelican Women's Championship in Belleair, Florida, US with a score of 62, the second lowest round of her professional career.
On 20 December, Maguire was named as the Irish Golf Writers’ Association Professional Player of the Year, only the second woman to be so honoured in the history of the award.
At the LPGA Drive On Championship held in Fort Myers, Florida, USA, she gained a three-stroke victory over Lexi Thompson with rounds of 66, 65, 67 for an 18-under-par total of 198.
Maguire finished the LPGA season winning her biggest ever prize money at the CME Group Tour Championship in Tiburon Golf Club, Naples, Florida, USA.
Maguire finished her 2022 season with fourth place at the LET Tour Andalucia Costa Del Sol Open De España in Villa Padierna Golf Club, Spain.
[59] She finished the tournament four strokes behind the winner, in a tie for 11th place, but the result was enough to elevate her to a career high of 10th in the world rankings, becoming the first Irish woman to break into the top-ten.
On 7 April, Maguire reached the final of the T-Mobile Match Play at Shadow Creek Golf Course, Las Vegas where she lost, 4 and 3, to Nelly Korda.