Lemos took up sport at the age of six, progressing through swimming, tennis, gymnastics, cycling, and mini-trampoline before gravitating toward motor sport. Her father attempted to steer her toward horseback riding but she was drawn instead to mini-motorbikes, then to motorcycles, and eventually to car racing. Contemporaries from her early years in informal off-road riding included fellow Portuguese driver Pedro Lamy. Her first competitive off-road rides came in 1990, and she later described the experience of entering desert racing at eighteen as having been "very bold," navigating extreme conditions including sand dunes without prior extensive preparation. The physical foundation for desert competition — stamina, balance, strength — was built across her varied sporting childhood.
Lemos entered rally raid competition on motorcycles in 1990 at the age of eighteen, establishing herself as Portugal's first professional female motorcycle pilot in international desert events. Between 1990 and 1992 she competed in international rallies in Tunisia, Morocco, Dubai, and Spain, in addition to national Portuguese events, before continuing her motorcycle career through to 1995. The technical demands of that era — heavy bikes with enlarged fuel tanks of around 30 to 40 litres and reinforced frames, navigated over hundreds of kilometres of unmapped desert stages — required considerable physical conditioning and navigational skill.
Lemos transitioned to automobiles in 1996, making her car debut at the Rali de Montelongo in a Nissan Micra 1.3 Super S as a course car. The following year she entered the Paris-Dakar Rally in the T3.1 prototype class, driving a Nissan Patrol GR for Team Dessoude with French co-driver Carine Duret. The pair won the Ladies Cup, with Lemos also finishing 35th overall in the car division. At 24, she became the youngest driver in the world to win the Ladies Cup in a car at the Dakar, and the first Portuguese woman to complete the event in an automobile. The Nissan Patrol used in that victory was later commemorated in the form of a toy-scale replica.
In 1999 Lemos competed in the TAP Rally de Portugal, a World Rally Championship round, for the Peugeot Esso Silver Team SG with co-driver Cristina Teixeira, driving a Peugeot 106 Kit Car. She finished 53rd overall and won the Ladies Cup. The overall podium of that edition — regarded at the time as a golden edition of the event — comprised Colin McRae and Nicky Grist first, Carlos Sainz and Luis Moya second, and Didier Auriol and Denis Giraudet third. She also competed at the 2003 Rallye ORPI Maroc. Her automobile racing career ran from 1996 to 2004.
After retiring from competitive driving, Lemos played a central role in securing Lisbon as the starting city for two editions of the Dakar Rally. Negotiations with Amaury Sport Organisation were conducted over several years; Lemos coordinated the bids from the late 1990s, managing the logistical and competitive challenges of positioning a Portuguese city against other European candidates. The 2006 edition, which began on 31 December 2005, opened with an 83-kilometre special stage near Lisbon followed by a stage south toward Portimão before the convoy crossed to Spain and Morocco. The 2007 edition, starting on 6 January in Lisbon, included 117 kilometres of special stage through the Alentejo region. Both editions attracted approximately 500 entries across motorcycles, cars, and trucks. Her racing career formally ended in 2006, and she subsequently covered the Dakar Rally as a journalist in 2009 and 2010.
Since 2012, Lemos has served as Head of the Family Office of Maude Queiroz Pereira, working as administrator and head financial advisor. She earned an MBA from the European School of Economics. She has two sons, Tomás (born 14 July 1998) and Martim (born 23 November 2000), from her first marriage to Portuguese banker Manuel Reymão Nogueira. On 7 October 2021, Lemos married Italian businessman Lapo Elkann — an heir to the Agnelli family and associated with Fiat — in a private civil ceremony in Portugal. Together they are involved in the LAPS Fondazione (Libera Accademia di Progetti Sperimentali), a foundation focused on humanitarian and social inclusion initiatives in Portugal and Italy.