Winston Aubrey Aladar Marshall (born 20 December 1987) is a British podcaster, political commentator and musician. He is the former banjoist and lead guitarist of the folk rock band Mumford & Sons. Prior to this he was in the bluegrass sleaze rap group Captain Kick and the Cowboy Ramblers. With Mumford & Sons, Marshall won multiple awards, including two Grammys and two Brit Awards. He has performed music with different supergroups and collaborated with Baaba Maal and HVOB. After leaving Mumford & Sons, Marshall hosted an interview podcast Marshall Matters on The Spectator from 2021 to 2023. In 2024, he launched his own politics and culture podcast, The Winston Marshall Show.

Winston Aubrey Aladar Marshall was born in Wandsworth, London, on 20 December 1987. His father is Paul Marshall, a British hedge fund manager who co-founded the Marshall Wace hedge fund and is the co-owner of GB News. His mother, Sabina de Balkany, is French and comes from a genteel European Jewish family. He has a sister, singer/songwriter Giovanna. His maternal grandmother was a novelist and property developer Molly de Balkany [fr], one of the first female property developers in France; Marshall's maternal great-uncle was the developer and collector Robert Zellinger de Balkany [fr]. Through Robert's marriages, Marshall's great-aunts include Genevieve François-Poncet, daughter of André François-Poncet, and Princess Maria Gabriella of Savoy.

Molly and Robert were the children of Hungarian-Romanian businessman Aladar Zellinger-Balkany, with the family relocating to France after World War II; they added the nobiliary particle "de" to the name upon arrival in France without actually being ennobled. Marshall has said that thirteen members of his family "were murdered in [...] the Holocaust", and that his maternal grandmother was a survivor. Marshall was educated at St Paul's School, an independent school in London.

Marshall began playing guitar aged thirteen and started a ZZ Top cover group called Gobbler's Knob. While the other members of Mumford & Sons were influenced by jazz, Marshall described the genre in 2013 as "the lowest form of art". He was inspired to play banjo after seeing O Brother, Where Art Thou?, switching to folk music and wearing his hair in dreadlocks. Marshall did not attend university, opting instead to pursue music. Marshall and future bandmate Marcus Mumford met as teenagers at church, playing worship music at a church group together and in a worship band, with Mumford saying Marshall is "magnetic to be around". Marshall, a multi-instrumentalist, has said that he chose to focus on banjo over guitar because there were fewer banjoists and so it was easier for him to get session jobs.

In the early 2000s, Marshall was in a bluegrass sleaze rap band called Captain Kick and the Cowboy Ramblers, who had songs such as "Jesse the Gay" and "Country London". Marshall was credited as "Country Winston Driftwood" and played the banjo, guitar, dobro, mandolin, and harmonica. With Captain Kick and the Cowboy Ramblers, Marshall ran a jam night "for teenagers who wanted to drink and play music" at Bosun's Locker, a tiny music club beneath a pasty shop on the King's Road in Fulham. The jam nights attracted a number of musicians who had an affinity for earthy acoustic music, including Noah and the Whale and Laura Marling.

The group Mumford & Sons came together in December 2007 after its four members had already been performing together in various configurations. Co-founder Mumford started songwriting after seeing Marshall's band Captain Kick, and other similar artists, perform while Mumford was at university in Edinburgh; Mumford was struggling at the time and found Marshall's music "a glimpse of salvation", especially as Marshall encouraged him to join them on-stage. The first Mumford & Sons performances took place in 2005 at Marshall's Bosun's Locker jam nights as informal performances of the musicians "like a hoedown". Mumford began performing here, and was joined by Marshall as well as other musician friends with whom he had previously performed, including Ben Lovett and Ted Dwane. As well as together, Dwane, Marshall, and Mumford all performed with Marling's band during the jam sessions. Mumford said that "eventually, Ted [Dwane], Ben [Lovett], and Winston [Marshall] stuck. It wasn't until [they] started writing songs together that [they] realized this was an actual band and not just a singer/songwriter with a couple of mates." Marshall played the banjo, guitars, dobro, and provided backing vocals, for the group, and was often identified as the comic relief of the line-up.

The band performed at Glastonbury Festival in 2008 and released their debut EP later the same year. Marshall and Mumford took jobs in the antique shop run by Marshall's mother in order to save money to produce and record music with Mumford & Sons. They toured with Marling and Johnny Flynn from 2008 to 2009; Marshall was nervous to perform in the United States, knowing that banjo is more common there than in the United Kingdom and their audience would know if he was good or not. In 2009, they cut their tour songs as their first album. The album, Sigh No More, on which Marshall is credited as "Country Winston", was released that year along with the single "Little Lion Man"; written by Mumford, the song was nominated at the 2011 Grammy Awards as Best Rock Song. The band was nominated for the Grammy for Best New Artist, and performed at the ceremony with Bob Dylan and the Avett Brothers. Sigh No More won the Brit Award for British Album of the Year in 2011.

The album was influenced by the music of Fleet Foxes, the Avett Brothers, Kings of Leon and Gomez; for Pitchfork, Stephen Deusner wrote that the band made this clear by pushing their musical references "with a salesman's insistence." It was released to minimal attention but steadily garnered more positive reviews, and while Deusner criticized the album as derivative, he was impressed that "there are some unexpected textures, mostly courtesy of some guy calling himself Country Winston playing banjo and dobro." The success of the bluegrass banjo-led album placed Mumford & Sons as the breakout of nu-folk music. They followed the album with near-constant touring, cementing their presence, though concert reviews were also mixed, criticizing the repetitiveness of the samey setlist while acknowledging the crowd's enjoyment. Chris Richards of The Washington Post added that the musicians' stage presence, particularly Marshall "thrusting his pelvis like a bluegrass Rick James", was irritating.