CS 121 was created by Harry Lewis in 1978 (though it was called AM 108 until CS got its own prefix in 1983) and taught mostly by him from then until 2016. Harry credits much of the course’s success to the wonderful teaching fellows he’s had over the years, many of them now faculty at Harvard and other universities, including Sanjoy Dasgupta, Bill Gasarch, Joe Hellerstein, David Karger, Michael Kearns, Lillian Lee, Milena Mihail, Michael Mitzenmacher, Grant Schoenebeck, Salil Vadhan, and many others.

See Madhu Sudan’s webpage for the Fall 2020 and Fall 2021 offerings.
| Name | Position | Photo | |
|---|---|---|---|
| Boaz Barak (he/him) | Instructor | boaz@seas.harvard.edu | ![]() |
| April Chen (she/her) | Head TF | aprilchen@college.harvard.edu | ![]() |
| Daniel Sheremeta (he/him) | Extension TF | danielsheremeta@college.harvard.edu | ![]() |
| Elijah Tai (he/him) | Patel Fellow | elijahtai@college.harvard.edu | ![]() |
| Alvin Zou | TF | alvinzou@college.harvard.edu | ![]() |
| Christy Jestin (he/him) | TF | christyjestin@college.harvard.edu | ![]() |
| Diego Gutierrez (he/him) | TF | diegogutierrez@college.harvard.edu | ![]() |
| Evan Howard (he/him) | TF | evanhoward@college.Harvard.edu | ![]() |
| Fabrizio Serafini | TF | fserafini@college.Harvard.edu | ![]() |
| Gabriel Wu (he/him) | TF | gabrielwu@college.harvard.edu | ![]() |
| Lucy Jiao (she/her) | TF | Lucyjiao@college.harvard.edu | ![]() |
| Matthew Smith | TF | matthewsmith@college.harvard.edu | ![]() |
| Priya Malhotra | TF | priyamalhotra@college.harvard.edu | ![]() |
| Ye Joo Han (she/her) | TF | yejoo_han@college.harvard.edu | ![]() |
| Depen Morwani (he/him) | Volunteer TF | dmorwani@g.harvard.edu | ![]() |
| Name | Role | Picture | |
|---|---|---|---|
| Boaz Barak | Instructor | cs121@boazbarak.org | ![]() |
| Brian Ramirez | Administrator | bramirez@gse.harvard.edu | ![]() |
| Daniel Chen | Head TF | chen_daniel@college.harvard.edu | ![]() |
| William Burke | Extension TF | wburke@g.harvard.edu | ![]() |
| Serena Davis | Patel Fellow | serenadavis@college.harvard.edu | ![]() |
| Raymond Lin | TF | rlin@college.harvard.edu | ![]() |
| Laura Pierson | TF | lpierson@college.harvard.edu | ![]() |
| Nathan Contreras | TF | nathancontreras@college.harvard.edu | ![]() |
| Richard Xu | TF | raxu@college.harvard.edu | ![]() |
| Nari Johnson | TF | njohnson@college.harvard.edu | ![]() |
| Michele Wang | TF | michelewang@college.harvard.edu | ![]() |
| Prayaag Venkat | TF | pvenkat@g.harvard.edu | ![]() |
| Noah Singer | TF | noahsinger@college.harvard.edu | ![]() |
| William Fu | TF | wfu@college.harvard.edu | ![]() |
| Alex Chin | TF | alexanderchin@college.harvard.edu | ![]() |
| Lana Gorlinski | TF | lgorlinski@college.harvard.edu | ![]() |
| Alex Kieras | TF | akieras@college.harvard.edu | ![]() |
| Pratap Singh | TF | pratapsingh@college.harvard.edu | ![]() |
| Pranay Tankala | TF | pranay_tankala@college.harvard.edu | ![]() |
Drawing of Boaz by CS 121 student Laura Chapman.
| Name | Role | Picture | |
|---|---|---|---|
| Boaz Barak | Instructor | cs121@boazbarak.org | ![]() |
| Brian Sapozhnikov | Head TF | briansapozhnikov@college.harvard.edu | ![]() |
| Albert Chalom | TF | achalom@college.harvard.edu | ![]() |
| Alexis Ross | TF | alexis_ross@college.harvard.edu | ![]() |
| Charles O’Mara | TF | comara@college.harvard.edu | ![]() |
| Daniel Chen | TF | chen_daniel@college.harvard.edu | ![]() |
| David Li | TF | davidli27606@gmail.com | ![]() |
| Jambay Kinley | TF | j_kinley@college.harvard.edu | ![]() |
| Jane Ahn | TF | jane_ahn@college.harvard.edu | ![]() |
| John Shen | TF | jshen@college.harvard.edu | ![]() |
| Josh Seides | TF | jseides@college.harvard.edu | ![]() |
| Laura Pierson | TF | lcpierson73@gmail.com | ![]() |
| Pranay Tankala | TF | pbt2017@gmail.com | ![]() |
| Raymond Lin | TF | rlin@college.harvard.edu | ![]() |
| Theresa Nguyen | TF | nguyenn@college.harvard.edu | ![]() |
| Wanqian Yang | TF | yangw@college.harvard.edu | ![]() |
| William Fu | TF | wfu@college.harvard.edu | ![]() |
| Hikari Sorensen | Extension TF | laurenhikarisorensen@gmail.com | ![]() |
| Eric Lu | Patel Fellow | ericlu01@g.harvard.edu | ![]() |
| Yueqi Sheng | Advanced section | ysheng@g.harvard.edu | ![]() |
| Chi Ning Chou | Advanced section | chiningchou@g.harvard.edu |
| Name | Pic | Role |
|---|---|---|
| Boaz Barak | ![]() |
Instructor |
| Salil Vadhan | ![]() |
Co-instructor |
| Gabe Abrams | ![]() |
Education Tech |
| Juan Perdomo | ![]() |
Head TF |
| Mark Goldstein | TF (extension) | |
| Chan Kang | ![]() |
TF (extension) |
| Aditya Mahadevan | ![]() |
TF |
| Brian Sapozhnikov | ![]() |
TF |
| Gabe Montague | ![]() |
TF |
| Jessica Zhu | ![]() |
TF |
| John Shen | ![]() |
TF |
| Juan Esteller | ![]() |
TF |
| Karl Otness | ![]() |
TF |
| Katherine Binney | ![]() |
TF |
| Stefan Spataru | ![]() |
TF |
| Susan Xu | ![]() |
TF |
| Tara Sowrirajan | ![]() |
TF |
| Thomas Orton | ![]() |
TF |