Lee had a far weaker season in 2012. She finished 25th on the money list with nearly 134 million won earned. Her best result was a runner-up finish at the EDaily Livart Ladies Open in April. She had one other top ten besides that, a 7th.

Lee managed to up her game again in 2013, finishing 7th on the money list with nearly 350 million won earned during the year. The undoubted highlight of her year came at the KLPGA's final Major of the year, the KB Star, which she won for her first Major victory. It says something about her week that the other three Major winners of 2013 on the KLPGA were also the top three players on the money list.

In addition to the win, she had two thirds, a fourth and two fifths among her 8 top tens on the year. She capped her year with a win at the unofficial Queen of Queens event, a special tournament featuring only the top players on tour. Lee has definitely established herself as one of those players!

Lee made a little more than 200 million won in 2014, finishing 21st on the money list. She had only five top tens, but one of those was a win at the EDaily Ladies Open.

Lee finished 27th on the money list in 2015. She had five top tens, her best finish a runner-up at the Saint-9 Masters in late April. She started 2016 well, notching a runner-up finish at the Mission Hills World Ladies Championship, an event jointly sponsored by the KLPGA and the LET.

In 2016, Lee had an excellent season on the KLPGA tour. She finished 4th on the money list with over 665 million won earned. She won the MY Munyoung Queens Park Championship in July and the Honma Golf Classic in late October. She also collected three other runner-up finishes and 14 total top tens.

Lee played at the ING Champions and the Kowa Queens team events, both times representing the KLPGA tour. At the Kowa, Lee teamed with Hae Rym Kim to beat Australia 4 & 3 and with Su Yeon Jang to win over Japan 3 & 2. She halved her singles match against Kotone Hori; she was the only Korean player who did not win her singles match.

At the ING Champions, she teamed with Jin Young Ko to beat Eun Hee Ji and MJ Hur 1 up, and with Seon Woo Bae to lose to Hee Young Park and Chella Choi 3 & 2., She lost in singles to Hyo Joo Kim 1 down.

Lee's 2017 season was almost as good as her 2016 was. She finished 7th on the money list, earning over 511 million won. She won a Major, the Hite Cup, and accumulated 9 top tens and a bunch more top twenties. She also played her first LPGA Major, the US Women's Open, but missed the cut.

Lee had another strong season in 2018. She finished 11th on the money list, with more than 434 million won earned. She had 11 top tens during the year, including a win. She also played in the OrangeLife Champions event for team KLPGA. She teamed with Da Yeon Lee to beat Jennifer Song and Chella Choi, and with Hye Jin Choi to square her match against Inbee Park and Jeong Eun Lee 5. However, in singles she was utterly demolished by So Yeon Ryu 7 & 5. The LPGA won the match 13-11.

Seung Hyun finished 49th on the 2019 KLPGA money list with around 133 million won earned. Her best finish by far was a 2nd place at the Celltrion Queens Masters early in the year.

The world was rocked by the Covid19 pandemic in 2020. The KLPGA and LPGA canceled or postponed many events. Lee nonetheless played a fairly full schedule, she just didn't have a very good year. She earned just shy of 35 million won all season, 98th on the money list. Her best finish was a 20th. She will probably lose full playing privileges on the KLPGA for 2021 given that result.

Lee only played three KLPGA events in 2021, with only one cut made. She didn't play after that and got married and announced her retirement in 2023, appearing at the NH Investment & Securities Championship to say bye to her fans.