Mohan has said that from chidhood she has been influenced by Lata Mangeshkar, Asha Bhosle and Kishore Kumar. She considered Mangeshkar as her "greatest Teacher for playback", while she credited A. R. Rahman for making her sustain her standard; "He is a task master but he gets the best out of you. His standards are very high, be it a recording or live performance". Mohan has also been influenced by many artists outside the country. She considered herself as a fan of John Mayer for his inspiring style of writing lyrics. Mohan credits the 1971 released song "Imagine" by John Lennon for inspiring on achieving her dreams with the "right kind of dedication".

In 2003, Mohan was one of the winners of the Channel V's reality television show Popstars, subsequently being chosen for Aasma—a pop group formed with the other winners of the show—where she got the chance to perform along with Bryan Adams. Insisted by Deepak Gattani, who manages A.R. Rahman's concert tours, Mohan managed to catch the attention of Rahman when she randomly sent a demo CD to him and was offered a chance to join his musical troupe. While she was assisting Lobo, he proffered Mohan to be featured in a supporting role in Imtiaz Ali-directed film, Socha Na Tha (2005), while Lobo was working as the Choreographer in the film. In 2009, Mohan participated in the Star Plus show Music Ka Maha Muqqabla, where she was part of the winning team "Shankar's Rockstars" led by Shankar Mahadevan.

During the year, she teamed up with Ankit Tiwari for "Aalif Se" in Mr. X and worked with Shankar–Ehsaan–Loy for "Sarfira" in Katti Batti, where R.M Vijayakar from India West stated that "Mohan stand out as the biggest thing in film". She collaborated with Rahman for the Tamil song "Mersalaayitten" included in the Soundtrack of I, performed along with Anirudh Ravichander. According to International Business Times, Mohan "chips in" by rendering the title word in a "porsche" way. Later the year, Mohan was roped in to perform the song "Neeyum Nannum" from Naanum Rowdydhaan which was composed and co-sung by Ravichander. Besides she performed a low-pitch song "Kohila" from Ko 2, co-sung and composed by Leon James. She was then heard in a Himesh Reshammiya's composition; "Tod Tadaiyya" from Prem Ratan Dhan Payo. The last release of the year featured Mohan in an Amaal Mallik composition; a recreation of the song "Tumhe Apna Banane Ka" from Sadak (1991). Included in the album Hate Story 3, she performed the song along with Armaan Malik. Applauding Mohan's rendition of the song, Composer Mallik noted; "I made her sing completely baritone [with this song]. I made her sing like a sensuous goddess. She evoked a voice she never knew she had". On International Women's Day, she released her single "Udne De" which was composed, sung and co-written by herself, as a dedication to all women in the wake of the Nirbhaya incident.

Besides her career in music, Mohan has also contributed to various charities. In October 2014, she performed at the "Hum Hain Umeed E Kashmir" concert in Ballia, in an appeal for donation to support rehabilitation of those who suffered during the Kashmir flood. The same month, Mohan took part in the musical concert held in New Delhi for raising funds for the flood affected people of Assam. In June 2016, she performed at Smile Foundation's charity gala dinner, to support the cause of empowerment of underprivileged children and youth. In January 2017, she collaborated with United Nations on a project aimed at empowering women, ending human trafficking and promoting gender equality. Her single "Udne De" was selected for the United Nations Voluntary Trust Fund Project titled "Music to Inspire-Artists united against Human Trafficking".

Mohan's biggest release of 2015 came with Amit Trivedi's Bombay Velvet, where she performed six jazzy tracks for the album. Trivedi was in search of a voice with an "Asha Bhosle meets Nina Simone" tonal quality for Anushka Sharma's Jazz singer character Rosie in the film, when he considered Mohan as the choice. According to The Indian Express, "what has worked" in the song "Mohabbat Buri Bimari" is Mohan's extemporisation in the middle of the track—with all the hiccups, laughs and squeals in place. The film marks the first time she read a script before recording a track to the respective film. "I was asked to sing just like how I would perform live". She recorded the songs at the studio dressed like a jazz singer, with people around her to cheer her. For another track "Dhadaam Dhadaam", Mohan was locked up in a room and was asked to "feel the pain of someone who's going through a break-up". Describing her time recording the song, she said; "I ran a fever after that song and you can almost hear the tear in my voice towards the end". Additionally, Mohan recorded a track titled "Naak Pe Gussa" for the film, which was inspired by K. M. Nanavati v. State of Maharashtra case. Mohan again collaborated with Trivedi in Shaandaar where she performed both "Nazdeekiyaan" and "Senti Wali Mental" for the film.

In 2017, Mohan recorded the Star Parivaar Anthem of the year, "Khoobsurat Star Parivaar" alongside Jubin Nautiyal. She also performed two songs for the web series titled "Mixtape" produced by music label T-Series. The fusion of "Dua" from Shangai and "Saware" from Phantom, performed along with Salim Merchant was received positively among critics. In spite of featuring in the single "Man Marziyan" she was heard in several tracks recorded for films. She was heard in an upbeat composition by Rahman, along with Arjun Chandy and Savithri R Prithvi for the Soundtrack album Ok Jaanu. Titled "Jee Lein", it received mixed reviews from critics. She was next heard in the Chirantan Bhatt's composed romantic track "Bawra Mann" performed with Nautiyal. The song was originally recorded for Singh Is Bliing (2015), but used in the Soundtrack album Jolly LLB 2 (2017), since it did not match with the theme of the former. Mohan collaborated with Pritam and Rochak Kohli for two albums; Jab Harry Met Sejal and Lucknow Central respectively, where she performed the song "Raula" with Diljit Dosanjh for the former. Additionally, she contributed to the music album of Baadshaho by performing a retro-contemporary fused item song "Piya More" with Mika Singh for an Ankit Tiwari-composition and also by recording the recreated version of "Keh Doon Tumhe" from Deewaar (1975). Titled "Socha Hai", it was removed from the film due to problems with music rights while "Piya More" was also altered slightly due to the legalities, since it does sounds "similar to what Tiwari has palmed off to another producer".

The following year, Mohan collaborated with Reshammiya in two other films; Sanam Teri Kasam and Teraa Surroor. "Haal-E-Dil" from the former received acclaim from critics. India West praised Mohan in their review of the music album; "Her resonant timber moves to soothing and back to haunting in an instant with enviable skill". She garnered her second Filmfare nomination for Best Female Playback Singer for the song "Sau Aasmaan" from Baar Baar Dekho. Composed by Mallik, the song was critically appreciated while Suanshu Khurana in her review wrote: "Mohan sing it in a voice we haven’t heard before—slightly operatic and falsetto singing". Apart from singing songs for films, Mohan performed alongside Mohit Chauhan in a music video of the TV show Yeh Hai Aashiqui and the duo was featured in some of the episodes in the series as musical narrators. She was also part of the music reality show The Voice India Kids as one of the mentors, along with Shaan and Shekhar Ravjiani. In the year end, she served as a coach in the second season of the Indian reality talent show The Voice.