Her biggest success came in early 2015 when she reached her first WTA Tour final in January, followed by a fourth round major event appearance at the Australian Open.

The streak ended when she earned a wildcard for the 2014 US Open main draw, which she capitalized on for her first major match-win.

[3][4][5] Her mother (Gaby née Gamberg) coaches her, her father is Dan Brengle, and she has a brother named David.

[7] In 2006, she won the Easter Bowl doubles championships with Kristy Frilling, defeating Sanaz Marand and Ashley Weinhold in the final.

Brengle and Julia Cohen were the top seeds at the 2007 French Open girls' doubles competition, but the team lost in the first round.

Seeded seventh, Brengle lost in the final of the Wimbledon girls' singles competition to Urszula Radwańska in three sets.

Brengle and Chelsey Gullickson reached the girls' doubles semifinals then lost to top seeds and eventual champions Pavlyuchenkova and Radwańska.

Accepted into the Australian Open main draw, Brengle lost to ninth-seeded Patty Schnyder.

In 2008, Brengle received a wildcard into the French Open (after winning a playoff tournament), defeating Ahsha Rolle in the finals.

At College Park, she defeated recent Wimbledon third rounder Melinda Czink to win her first WTA Tour match since Quebec City in 2009.

Brengle had a strong start to her 2014 season, qualifying through to the main draw at the Hobart International, but was narrowly defeated in the first round by top seed Samantha Stosur in a final-set tiebreak.

Later in the year, she was awarded a wildcard into the main draw of the US Open, and she recorded her first Grand Slam match win over Julia Glushko of Israel.

She moved into the top 100 for first time on September 29, 2014 after winning the $50k Redrock Open in Las Vegas, defeating Nicole Vaidišová, Kateryna Bondarenko and Michelle Larcher de Brito.

Then, she won in straight sets against both Irina Falconi and CoCo Vandeweghe, eventually losing in the fourth round to Madison Keys, 2–6, 4–6.

[13] As the top seed at the Midland Tennis Classic, Brengle lost in the first round to Jacqueline Cako.

[15] Brengle began her 2020 season at the Brisbane International and lost in the second round of qualifying to Yulia Putintseva.

[19] At the US Open, she reached the third round for a second time in her career with wins over Arina Rodionova[20] and 19th seed Dayana Yastremska,[21] before losing to Shelby Rogers.

[22] Brengle started her season at the Yarra Valley Classic where she lost in the first round to Anastasija Sevastova.

[25] Getting past qualifying at the Adelaide International, she lost in the first round to eventual champion, Iga Świątek.

[27][28] Brengle started the 2022 season at the Melbourne Summer Set 1 in which she lost in the second round to eventual finalist, Veronika Kudermetova.

[29] At the Adelaide International 2, she reached the quarterfinals where she retired against Alison Riske due to a calf injury.

She retired during the third set of her first-round match against Emma Navarro due to a left knee injury.

[41] Seeded second at the first edition of the Veneto Open, she lost in the first round to eventual finalist Sara Errani.

[45] Getting past qualifying at the Canadian Open in Toronto, she was defeated in the first round by tenth seed Coco Gauff.

[46] As the top seed at the Odlum Brown Vancouver Open, she reached the quarterfinals and lost to Emma Navarro.

[50] As the top seed at the Central Coast Open in Templeton, California, she won her 18th ITF title by beating Robin Montgomery in the final.

[56] At the Linz Open, she got her first win of the year by beating Austrian wildcard Julia Grabher, in the first round.

[60] At the first edition of the Texas Open in Austin, she lost her second-round match to eventual champion Marta Kostyuk.

[64] Only main-draw results in WTA Tour, Grand Slam tournaments, Fed Cup/Billie Jean King Cup and Olympic Games are included in win–loss records.