In 1908 Lucas made his motion picture debut in Griffith's "The Greaser's Gauntlet", appearing in more than 50 of these short (usually 17 minutes) films over the next two years. In 1910 while still acting, he wrote the script for Griffith's film "Sunshine Sue", which was followed by many more scripts by 1924. Lucas also began directing in 1912 with Griffith on "An Outcast Among Outcasts", and directed another 44 films over the next 20 years. In early 1916 he starred as John Carter in "Acquitted", about which "Photoplay" wrote, "No single performance in the records of active photography has surpassed his visualization of the humble book-keeper in "Acquitted".