Born in Saikul, Manipur, Doungel started his career in the youth team of JCT before joining East Bengal of the I-League in 2011.
Doungel came on as a 71st-minute substitute for Chidi Edeh and then scored a 77th-minute goal for East Bengal, however, the club still went on to lose 3–2.
[8] He then scored his second goal of the season on 23 March 2014 against Rangdajied United after coming on as a 53rd-minute substitute for James Moga.
[11] On 5 May 2014, following the conclusion of the 2013–14 season, it was announced that Doungel had signed for Shillong Lajong who also play in the I-League.
[12] On 3 June 2015, Bengaluru announced the signing of Len from Shillong Lajong on a two-year deal.
On 20 May 2019, Doungel signed a two-year contract with Goa[15] on a free transfer from Kerala Blasters.