In 2018, Noh quickly climbed into the upper reaches of girls amateur golf rankings. She won the Hana Financial Group Se Ri Pak Junior Championship to earn a spot in the LPGA's KEB Hana Bank Championship, the annual LPGA event that takes place in South Korea.

Also in 2018, she won the California state championship again. Shortly after that, she won the Junior PGA Championship; her 24 under par score was the lowest in the history of the tournament.

Noh continued her torrid pace the very next week by winning the US Girls Junior, one of the most important amateur events for girls in the world. The following week, she won the Canadian Women's Amateur. Winning any of those events would have been impressive; winning all three was off the charts!

She also played the 2018 KEB Hana Bank and the Canadian Women's Open on the LPGA. In the latter she was low amateur.

Noh decided to skip college and turned pro late in 2018. She signed a sponsorship deal with Hana Bank and has already been featured in commercials for the company. But because she did not have membership on any tour, she spent 2019 playing in Monday qualifiers and as sponsor's exemptions.

She had a good deal of success going that route. She played brilliantly at the Thornberry Classic in early summer, eventually finishing tied for 6th, her first career LPGA top ten. Later she played her first Major, the Evian, and finished tied for 44th.

But neither of those results compared to what she did in late August in Portland as a Monday qualifier. She started the Cambia Classic with a 65, but it was a third round 64 that put her in great position to win her first LPGA event. During most of the final round she had a three shot lead, but she struggled all day, and in the end Hannah Green managed to pass her and win. Still, it was a great effort for the 18-year-old, a solo second place.

Yealimi entered LPGA Q-Series in the Fall and wound up finishing solo third, the best score for a rookie in the field. She earned full LPGA membership for 2020.

In 2020, the whole world was rocked by the Covid-19 pandemic. The LPGA and KLPGA tours canceled and postponed many tournaments. Yealimi played 16 LPGA events in 2020, making all but one cut. For the most part she played decently but unspectacularly, but she did manage two top three finishes. At the Cambia in Portland, she once again found herself in contention. She reached the final hole needing just a par, but missed the fairway and made bogey to miss the playoff. She finished tied for third. At the Volunteers of America, she had a chance to play with two of her idols on Sunday, Inbee Park and So Yeon Ryu. All three players tied for second.

Noh made $415,000 for the year, finishing 25th on the money list. The LPGA extended the Rookie of the Year race through 2021, but at the end of 2020, she had the lead.

Yealimi also played two events on the KLPGA tour, but didn't contend in either.

Yealimi played a full season on tour in 2021, and as a result made a lot more money. She accumulated $708,000 during the year, although her money list position was pretty much the same as 2020: 27th. The start to her year wasn't strong, but things picked up for her in June, when she notched a top 20 at the Mediheal. She followed that with another at the KPMG, then managed a tie for third teamed with A Lim Kim at the Dow Great Lakes Bay Invitational.

Her best came next. She shot four rounds in the 60s at the Evian. She was a ways behind the leader Jeongeun Lee6 heading into Sunday, but was in the final group. However, Lee6 struggled on Sunday, and Noh surged into contention. On the final hole, she was just one shot behind the clubhouse leader Minjee Lee. But after a mediocre drive, she decided not to go for the green in two; she wound up with par, and missed the playoff that Lee won. It was by far her best Major result to date.

For the year she had three top tens and four more top twenties, and finished 3rd in the Rookie of the Year standings.

Yealimi also played on the 2021 Solheim Cup team, where she finished 2-1-0. Included in that was a singles win over England's Mel Reid. Noh also played at the Hana Bank Championship on the KLPGA, but missed the cut.

Yealimi had a notably worse season in 2022. She only managed two top tens, both ties for 10th, and one of those came at the team event when she was again paired with A Lim Kim (she also won a virtual golf competition when teamed with A Lim in 2022). She had another strong week at the HSBC in Singapore, where she shot a second round 64 en route to a tie for 17th. She ended up making a little over $225,000 in 2022, 86th on the money list, which was just good enough for her to maintain category 1 status for 2023.

Alas, 2023 was another rough season for Yealimi. At one point she missed 6 out of 7 cuts. She finally had her only top ten of the year in Arkansas in late September, a tie for 8th. She made just $119,200 all year, 122nd on the money list. She returned to Q-Series, where she finished tied for 17th and grabbed one of the final full cards for 2024. She will thus have category 14 status at the start of the season.