Yang had the talent to compete and even win AJGA events, but was not allowed to play due to her youth: the AJGA has a minimum age limit of 12 years. Shortly after her 12th birthday in 2007, she played her first AJGA event and finished third. At her second event a few weeks later, she did even better, finishing second. She captured the title at her third event, the Randy Smith Classic in Lubbock, TX, beating two significantly older players in a playoff. In so doing, she became the second youngest girl to ever win an AJGA event, (the youngest girl to ever win one had won before the 12 year age limit had been instituted). Yang was 12 years, 1 month and 8 days old when she won the Smith title. Later in 2007, she won the US Kids World Championship. She was named to the Rolex Junior All American teams in 2007 and 2008; she was the youngest Rolex All American in history.

Even later in the year, Julie was invited to play at a KLPGA event, the Inter-Burgo Masters. She did not make the cut, but it was still a good learning experience for the youthful golfer. In 2009, she played in three KLPGA events, making all three cuts and achieving best amateur status while still just 13 years old.

At age 14, Julie relocated to Europe, where she attended school in Scotland. She continued her winning ways there. Among her triumphs were wins at the Welsh Ladies Open Stroke Play Championship, the Danish International Ladies Amateur Championship, and the English Women's Open Stroke Play Championship. She was the youngest winner in history in all of those events.

Julie moved back to the States in 2011, and looks primed to continue her rise to prominence over here. Although she did not do well at the US Women's Amateur, losing in the second round, she did win the 2011 Women's Trans National Amateur Championship, where once again she was the youngest champion in history.

Early in 2011, Julie played at the Kia Classic on the LPGA tour, where she made the cut and finished tied for 46th.

Julie skipped a school year and graduated from high school in 2012. She joined Oklahoma State in early 2013. Among her notable achievements in 2013 were getting to the semifinals at the Women's Amateur Pub Links.

During Yang's junior year in college, she attended 2014 LPGA Qualifying School. She finished tied for 18th with several other players, meaning she needed to enter a playoff for the final full tour cards. Alas, she lost and only earned conditional status, but she turned pro anyway and joined the tour as a rookie in 2015.

Yang did not get into many fields in 2015, and only made one cut, at the JTBC Founders Cup. She finished 34th there. But she returned to Q-School in the Fall and played great. She finished tied for 10th to earn full status on tour for 2016.

Julie also played a couple of KLPGA events in 2015, with her best result a tie for 16th at the Posco Championship. She played the Symetra Tour as well, but finished well out of earning an LPGA tour card that way.

Julie started the 2016 well. In her second event, the Coates Championship, she achieved her first career top ten when she finished tied for 6th. She had one other top 20 and wound up making $116,785 for the year, a huge improvement over 2015. This placed her 93rd on the money list, good for a slight upgrade in her status to category 11 for 2017.

Alas, she struggled in 2017, making just one cut and less than $4,000 all year. She lost her playing privileges on the LPGA. In 2018, she played on the Symetra Tour. Her last recorded event there was in 2020; it's likely she has retired.