Im Yoona was born on May 30, 1990 in Seoul, South Korea. Her family consists of her father and an older sister. While growing up, she listened to girl group S.E.S and dreamed of becoming a singer. In 2002, she was cast in the SM Saturday Open Casting Audition and spent five years "doing nothing but constant training" in singing, dancing and acting. During her trainee days, she had low self-esteem about her low voice, and once thought of giving up singing in order to pursue an acting career. An SM choreographer persuaded her to continue, saying it would be "a waste to give up becoming a singer" with her "outstanding dancing skills". He also considered her as the best female dancer within the agency. Prior to debuting, Yoona was introduced to the public through various appearances in music videos and commercials; she first appeared in TVXQ's "Magic Castle" music video in 2005. She made her official debut as a member of Girls' Generation in August 2007, becoming the "center" of the group. The group gained significant popularity with the release of their hit single "Gee" in 2009. That same year, Yoona graduated from Daeyoung High School.
In May 2008, Yoona landed her first leading role KBS's drama You Are My Destiny, playing Jang Sae-byuk. On her first day of filming, she was sent home crying by the director after making a mistake and being told she "was not yet ready for the role". She also had difficulties at first with her crying scenes. Yoona would prove her worth as an actress with the role, and credited the director for helping her grow as an actress. The drama achieved viewer ratings of up to 41.5%, and Yoona became known for her character. She considered the role a turning point in her career, and won two "Best New Actress" awards at the 2008 KBS Drama Awards and 45th Baeksang Arts Awards.
In 2009, Yoona filmed MBC's drama Cinderella Man along with Kwon Sang-woo. She was not satisfied with her performance, which made her depressed. During the drama's press conference, she said although she "had the ambition to do well", she was not sufficiently prepared due to "juggling between acting and Girls' Generation's activities". In 2010, she appeared as a guest on SBS's variety show Family Outing and later joined season 2 of the same program as a permanent cast member. The program ran from February to July that year.
In March 2012, Yoona was cast in a lead role with Jang Keun Suk in KBS2's drama Love Rain. It was a fantasy drama about fate and how the offspring of an ill-fated couple who met in the 1970s, also manage to fall in love with each other. She played two characters, Yun-hee of the 70s and Ha-na of modern times. She used a different approach to acting, analyzing the characters and substituting herself in their place in order to feel their emotions. Although the drama lacked in domestic viewership and received some criticism for its failure to relate to the viewers, Yoona's acting received positive reviews. Yoon Ga-ee of OSEN wrote: "The speed at which her acting is improving is blinding. She has matured to the point where you want to ask, 'When did her acting get so good?' The criticism that trailed behind her during Cinderella Man is now nowhere to be found." Choi In-kyung of Hankook Ilbo said her acting was continually improving and "Yoona is completely immersed in her character and has now become 'Hana' herself." The drama garnered much positive overseas interest and was sold to Japan for $10 million, the second highest price for a KBS drama at the time, partly due to Yoona's popularity.
In December 2013, Yoona starred alongside Lee Beom-soo in KBS2's romantic comedy drama Prime Minister and I. Loosely based on the musical film The Sound of Music, Yoona played Nam Da-jung, a young and stubborn reporter who falls in love with the prime minister. The drama received low ratings, but Yoona was still noted for her acting. Lee Beom-soo praised her, saying "Acting has to go by logic, only when one understands can the audience understand too, Yoona is smart and did very well. I am anticipating her path down as an actress; at the same time, I want to give her applause". She won an Excellence Award at the 2013 KBS Drama Awards for the role. In 2014, Yoona was initially chosen to be the female lead for KBS2's drama Cantabile Tomorrow, but turned down the role to be in the Korean-Chinese romantic comedy movie Goodbye Ani. She graduated from Dongguk University in February 2015, receiving a lifetime achievement award at the graduation ceremony. Her fellow Girls' Generation member, Seohyun, attended the same university. That same year, Yoona filmed the Chinese drama Wu Shen Zhao Zi Long, set to be released later in the year.
Yoona in the music video for "Chocolate Love" (2009), which was used as a promotional song for LG Chocolate phone
Yoona has been called a "CF queen" due to her many television commercial films, and has been a spokesperson for various brands.CNN credited her as "one of the household names in the Asia-Pacific region" which has helped Korean beauty brands become popular in China. In 2010, she became the first idol to endorse S-Oil, a large South Korean petroleum and refinery company. In 2012, she appeared in at least 20 commercials and was ranked fifth among celebrities with the most commercial appearances by TVCF, South Korea's largest advertisement information site. In 2013, she became the first overseas endorser for Alcon Taiwan.
^""Nam Hee-suk and Choi Eun-kyung's Free Time"". (in Korean). August 6, 2008. approx.60 minutes in. KBS2. I noticed there is a lot of crying scenes in this drama. At first, I couldn't cry so I got scolded a lot. But since a few days ago, I've been reading the script and the story is so sad, that I can't help but to cry. Last time too, when Taepoong said "I don't need a younger sister like you", those words were so sad. All those scenes with him doing good things for me went through my mind.Missing or empty |series= (help);|access-date= requires |url= (help)