
Alexander began riding at the age of eight. She became interested in horses because her neighbor had a barn and she watched them ride on the weekends. The Avondale Pony Club in North Turramurra, New South Wales was where she first began riding. In 1995 she won the Australian Young Rider Championships. In 1998, wanting to ride against the top riders in the world, she moved to Europe, taking her horse, Mr. Dundee, with her to Belgium. In 1999, before beginning her own company, she competed for Ludo Philippaerts, a famous show jumper, for about three years.

In 2006 in Aachen Germany, she became the first Australian to make the final of the individual jumping competition at the World Equestrian Games, where she finished fourth despite entering the competition as 35th in world show jumping rankings. Brussels, Valkenswaard, London, Zurich, Cannes, Geneva, Vigo, and Doha are just few of the places where Edwina has won Grand Prix shows. She was selected for the jumping events at the 2008 Summer Olympics where she rode Isovlas Itot du Chateau. She placed 9th in the individuals and 9th in the team competition. She was the overall champion of the Global Champions Tour in both 2011 and 2012. Not only did she win twice in a row but she was the very first rider to win a total of one million euros of prize money on the tour. Also in 2012, at the age of 38, she rode in the individual show jumping for Australia at the Summer Olympics. She rode Itot Du Chateau and finished in a time of 81.77s with 4 faults. This put her in 20th place for the individual competition and for them team competition Australia was 10th. In 2016 Edwina won the Miami Beach Grand Prix, the first Gct round of the season. Edwina placed ninth in the Individual Showjumping during the 2016 Summer Olympics, with Lintea Tequila. She currently has Lintea Tequila, Califorina, and Carentina De Jonter as her main Horses.

On the 19th of March 2017 Edwina won the Saut Hermes competition in Paris, on the mare California. A week later, she announced an indefinite hiatus from competition.

Alexander attended Pymble Ladies College, in Sydney. She attained a Bachelor of Physical Education at the Australian College of Physical Education in 1995. In September 2011 she married Jan Tops who was also her trainer. Edwina is a dual citizen of Australia and the Netherlands and speaks some Dutch, but primarily speaks English and has retained her Australian accent. Edwina still competes for Australia even though she has been living in the Netherlands for 20 years. She is openly proud of her roots in the Suburbs of Sydney.

She suffered a serious fall in 2007 during a Grand Prix in Estoril, Porutgal, and split her lip. In 2012, she suffered a broken wrist and a concussion after falling, during a show in France.
Tops-Alexander is the most successful Female and Australian Showjumper. Edwina is also a strong advocate for Women in Sport, and was the Magic Millions Racing Women ambassador for 2014. In an interview in 2015, Edwina states that she does not see Showjumping as "Men against Women". She says she sees it as "Horses against Horses".
On the 28th of March, 2017, Tops-Alexander announced that she was putting her career on hold and leaving the sport as she prepared to give birth to her first daughter in August 2017. Chloe Cornelia Jennifer Tops was born on the 30th of July, 2017 in the Princess Grace Hospital Centre, Monaco.
The well-known designer label, Gucci, formerly sponsored Edwina until ceasing Sponsorship with all the brands riders in 2016. Tops-Alexander is sponsored by Equifit inc. and is endorsed by Adidas during the Summer Olympics. Connoly's Red Mills sponsors Edwina, And all her horses will be fed by this company for each of their individual needs. Edwina is also an ambassador for Jaeger-LeCoultre, the Swiss watch company.
Tops-Alexander has a strong interest in fashion and has made a permanent mark on Equestrian Style. She has also become one of the most recognisable athletes competing in Professional Showjumping.
Edwina has represented Australia at the 2008, 2012, and 2016 Summer Olympics. She also represented Australia at the 2002, 2006, 2010, and 2014 World Equestrian Games. She is regarded as the "Captain" of the Australian Showjumping Team, as she is one of the Senior riders.
Tops-Alexander has not announced if she will return to Individual or International competition in 2018, meaning the 2016 Summer Olympics was her last international competition as of 2017.