"The East Face is the classic route up Teewinot. It begins from Lupine Meadows trailhead. The trail starts from the north end of the parking lot on the west side. There is no sign but the trail is obvious as it heads straight toward Teewinot. The trail meanders through the sagebrush flats. Once it gets to the base of the mountain it starts switchbacking relentlessly up the hillside.
You should be able to see a waterfall to the left side of the trail. Most sources say there are at least eighteen switchbacks ascending up to the apex. You will know you are at the apex when you get close to timberline. It is one of the few relatively flat places on the entire route. From the apex, the trail climbs steeply up the ridge. You pass right beneath two prominent gendarmes known as the Idol and the Worshipper to your left. Soon you will be at the large east face snowfield that is so recognizable from the valley. I recommend using an ice ax here. By the end of summer, in some years, the snowfield has melted entirely and hiking is on talus and scree.
From the top of the main snowfield, scramble up broken 3rd class rocks slabs. Traverse to the left towards the V-shaped gully. Scramble up either side of the gully which is the crux pitch. This is rated as 4th class. If you get off route then you may encounter more difficult scrambling on the east face. It isn't hard to climb up but feels steeper when you downclimb it on the descent.
Once you make it to the top of this pitch there will usually be another snowfield above. The rock may be wet from melting snow. You can climb around it to the right on 3rd class rock. From there the route traverses toward the right side of the summit ridge. There is a climber's trail leading to it. From the top of the ridge you get your first view of the Teton Peaks and Cascade Canyon.
From here, continue traveling south along the narrow exposed ridgeline. You will be able to see down the west face of the mountain. You can't see the top of the mountain until it is right in front of you. It is a spectacular summit that has room for one person. The view of Mount Owen and the north face of the Grand is one of the best in the Tetons.
The preferred descent is back down the east face. If you are doing a traverse with Mount Owen then your descent is west. From the summit, scramble back down to the top of the gully. You can down climb the more solid and steep rock to the north or the loose but easier rock in the gully. Some people choose to rappel this instead of down climbing it. The hike down the east face route is hard on the knees and legs but is easy once you get back down to the trail."
** Most descriptions downplay the difficulty and danger of this route. The best route up can be tricky to find and there have been many fatalities on this route in both summer and winter seasons.