The origin of Mike Ehrmantraut in Breaking Bad could be credited to How I Met Your Mother. The character, played by Jonathan Banks, was introduced as a guest star in Breaking Bad season 2. Much of his early story arc revolved around Saul Goodman, another character who made his Breaking Bad debut in the second season.
Mike turned out to be one of the most complex characters from Breaking Bad. He was introduced as the middle man between Saul and Gus Fring. After he was bumped up to a more prominent role in season 3, Mike's arc expanded. As a private investigator, Mike cemented himself into many of Walter White's dealings. Mike considered Walt an enemy but they were later forced together down the line. In the end, Walt got the upper hand and killed Mike by the end of the series. Banks' performance as Mike garnered a number of nominations and award wins. The end of Breaking Bad wouldn't conclude Banks' time portraying the character since he soon joined the spinoff, Better Call Saul.
The character of Mike probably wouldn't have existed if it wasn't for Banks' co-star, Bob Odenkirk. The actor's character, Saul Goodman, was introduced as a flamboyant attorney who worked at an Alburquerque strip mall. Walt and Jesse go to Saul after they needed help with Badger's legal troubles. That season was being filmed in 2009, at the same time Odenkirk was portraying Marshall's boss, Arthur Hobbs, on How I Met Your Mother. Odenkirk was only scheduled to appear in a handful of episodes in Breaking Bad season 2 but he couldn't make them all because of his commitment to How I Met Your Mother. To fill in those blanks left by Saul's absence, the series created Mike Ehrmantraut. Odenkirk confirmed the connection in an interview with Rolling Stone:
"I promise you I thought I was up for three episodes of Breaking Bad — well, they wanted me for four, but I could only do three ’cause I was in How I Met Your Mother. They actually added the character of Mike because I couldn’t make that fourth week, and they needed another character to get that information across, so that’s amazing right there. Thank you, How I Met Your Mother."
Odenkirk's arc on How I Met Your Mother lasted eight episodes between 2008 until 2012. If he hadn't booked that role, there may not have been a need for Mike in Breaking Bad. The characters could have evolved very differently if the chips didn't fall the way they did in 2009. Bryan Cranston must have repaid the favor to How I Met Your Mother by returning to the sitcom following his time as Walter White. Cranston portrayed Hammond Druthers for two episodes between 2006 and 2007 and reprised his role in 2013.
When Odenkirk worked on both How I Met Your Mother and Breaking Bad, the sitcom was more popular than the AMC series at the time. Odenkirk wasn't sure which role was more of a priority in his career. In the end, it worked out great for all involved. How I Met Your Mother lasted nine seasons and Breaking Bad became a pop-culture juggernaut. Both Odenkirk and Banks became critically acclaimed stars in their Breaking Bad role and were used as the focus of the prequel series, Better Call Saul. The series is set to return for its fifth season in 2020. Banks has also been confirmed to appear in El Camino: A Breaking Bad Movie and there's a reason to believe that Odenkirk will appear as well.