Born in Surabaya in 2010, Osten Cristo Harianto is a young, talented Indonesian pianist who consistently shows excellence in the fields of STEM, the arts, international economics and business competitions, and community service. He is the first Indonesian to be awarded the Double Legend Award from the World Math Invitational (WMI) Finals after winning six gold and diamond awards in six consecutive years. He achieved an individual Gold Award in his final year of Junior High School at SIMOC 2024 (Singapore International Math Olympiad Challenge). Near the end of 2024, Osten was selected to join the Indonesian national team for the 14th ASMOPSS (Asian Science and Mathematics Olympiad for Primary and Secondary Schools), held by the Surya Institute, founded by Indonesian physicist Prof. Yohanes Surya. He won a bronze medal in the theoretical round and 2nd runner-up in the exploration round for the Secondary category.

Besides mathematics, he has consistently been a medalist at the VNJSO (Vanda National Junior Science Olympiad) Global Final for nine years, and his most recent award is a Silver Medal in the STEAM Ahead Competition in December 2024. In 2024 and 2025, Osten also received a scholarship to join the NJCO (National Junior Cybersecurity Olympiad) and achieved Silver and Bronze Medals.

At 15 years old, he held a two-hour charity piano recital attended by over 150 people at Amadeo Hall, Surabaya. He passed ABRSM Grade 8 with distinction at the age of 12 and has won many national and international piano competitions. He has been invited to perform in gala concerts in Shanghai, Singapore, Taiwan, Jakarta, Semarang, Bali and Surabaya. At the age of 13, he had already won 1st prize at the prestigious Ananda Sukarlan Award. He also received the Platinum Award at WPTA Singapore 2020, 1st prize at the Osaka Music Competition 2019 and many other accolades.

As a FIDE-rated international chess player, Osten is also keen on learning social sciences. His essay won a full scholarship in the SDGs Competition 2025: Blueprints for a Sustainable Community, hosted by UNESCO and Nisai Learning. He was one of the finalists in the Economics World Cup 2025 in partnership with Oxford University, and his team won 1st prize in the YABO (Young Achiever Business Olympiad) 2025 held at Ciputra University.